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Silent_Hunter
01-04-2007, 12:08 AM
SSK 6.5 MPC: Best Assault Rifle Cartridge for 21st Century Warfare?
Posted on Sunday, December 31 @ 11:54:47 PST by davidc (http://www.defensereview.com/)
http://www.defensereview.com/images/topics/AvatarAmmo.jpg (http://www.defensereview.com/modules.php?name=News&new_topic=10) by David Crane
david at defensereview.com
Small arms designer/developer J.D. Jones (http://www.sskindustries.com/ssk.htm) of SSK Industries (http://www.sskindustries.com/) has developed what may just prove to be a superior solution to the 6.8x43mm SPC (http://www.defensereview.com/modules.php?name=News&file=article&sid=383) (a.k.a. 6.8 SPC (http://www.defensereview.com/modules.php?name=News&file=article&sid=383)) and/or 6.5 Grendel (http://www.65grendel.com/) (6.5x39mm) cartidges as a replacement for the 5.56x45mm NATO cartridge for U.S. military general infantry and Special Operations (USSOCOM) use. Mr. Jones is calling it the 6.5mm Multi-Purpose Cartridge (http://www.sskindustries.com/6_5mpc.htm) (6.5 MPC (http://www.sskindustries.com/6_5mpc.htm)), and on paper, it looks pretty good.
The 6.5 MPC (http://www.sskindustries.com/6_5mpc.htm) (6.5x45mm) utilizes the...


standard 5.56x45mm NATO/.223 Rem. case. However, to maximize powder capacity (and thus projectile velocity and ballistic/terminal performance), Mr. Jones (http://www.sskindustries.com/ssk.htm) pushed the case shoulder back a tad and increased the size of the case neck so it would accept a 6.5mm bullet. The result? A 95-grain "SSK Solid" bullet travelling at a muzzle velocity (MV) of approx. 2600 fps out of a 12-inch (12") barrel and approx. 2800 fps out of a 20-inch (20") barrel. So, were' guessing around 2700 fps out of a 16-inch (16") barrel (unconfirmed/unverified). Pretty respectable. Muzzle velocities for the 110-grain Sierra HP version of the 6.5 SPC are 2480 fps (12") and 2731 fps (20"). MVs for the 120-grain "SMK" round are 2220 fps (12") and 2400 fps (20"). 120-grains is the upper limit of bullet weight for this cartridge. Anything above that affords limited ballistic returns. Impact energy (terminal energy) is reportedly 30-50% greater for the 6.5 MPC (http://www.sskindustries.com/6_5mpc.htm) over the 5.56mm NATO, depending on bullet weights and types, while the weapon remains highly controlloble on full-auto.
The 6.5 MPC page (http://www.sskindustries.com/6_5mpc.htm) at the SSK Industries website (http://www.sskindustries.com/) mentions that they've fired a 107-grain SMK round at 2400 fps out of a weapon with a 12"-barreled CQBR-type upper receiver and that effective engagement range is 300+ yards. With longer barrels, the distance is increased.
So, why the 6.5 MPC instead of the 6.8 SPC (http://www.defensereview.com/modules.php?name=News&file=article&sid=383)? Ease and cost of conversion (weapons conversion), ammo capacity, and ammo weight (ammo carry capacity at a given load weight). The 6.5 MPC utilizes standard AR-15/M16/M4/M4A1 magazines and bolts, and will function in both the SOPMOD M4/M4A1 Carbine and belt-fed FN M249 SAW/LMG, provided you switch out the barrel(s). No further modification is reportedly necessary. Mag capacity for the 6.5mm MPC is 30 rounds (although you might still want to down-load it to 28, as many do with 5.56mm ammo for reliability purposes). The 6.8mm SPC doesn't stack properly in standard 5.56mm M4/M4A1 mags, and the magazines that have been developed for it limit ammo capacity to 25 rounds, as opposed to 30 rounds, so the 6.8 SPC mags will fit inside current military mag carry pouches. You can also use 5.56 NATO *****per clips to load 6.5 MPC rounds into the mag. At present, there are no 6.8 SPC *****per clips.
6.5 MPC ammo will reportedly feed as reliably as 5.56x45mm NATO ball ammo can utilize standard M27 links (belt links) with no modification, so it will feed reportedly feed reliably through the M249 SAW. You only have to switch the barrel to 6.5mm caliber. Not so with the 6.8 SPC, which would require modification to the M27 link.
The 6.8 SPC cartridge weighs approx. 40% more than the 5.56mm NATO cartridge. That, combined with the fact that 6.8 SPC mags are made of steel instead of aluminum (making the magazine roughly twice as heavy), means that the infantry warfighter or Spec-Operator will be able to carry less rounds of 6.8 SPC vs. 6.5 MPC or 5.56 NATO.
Reported ammo carry capacity breakdown for the various cartridges at the same carry weight (specific weight unkown, and unconfirmed/unverified):
5.56 NATO: 10 x 30-round mags = 300 rounds
6.5 MPC: 9 x 30-round mags = 270 rounds
6.8 SPC: 7 x 25-round mags = 175 rounds

DefenseReview recommends that you read Stan Crist's article on the 6.5mm Multi-Purpose Cartridge (http://www.sskindustries.com/6_5mpc.htm) in the #44 issue of Special Weapons for Military & Police (http://www.harrisoutdoorgroup.com/specialweapons.html) (SWMP (http://www.harrisoutdoorgroup.com/specialweapons.html)) magazine. That issue has a photo of a U.S. Ordnance (http://www.usord.com/) M60E4/MK43 Mod1 Commando (http://www.usord.com/M60E4Comm_USORD.html) "light machine gun series" GPMG (7.62x51mm) on the cover, and the article is titled "SSK 6.5mm MPC: Multi-Purpose Cartridge delivers bet-your-life performance." While SSK Industries Website indicates that they developed the 6.5 MPC round at the behest of one Brian Hormberg (USMC), it should perhaps be noted that Stanley Crist mentions in his article that he wrote about his own idea for a 6.5mm assault rifle cartidge in the #36 Issue of Special Weapons for Military and Police (http://www.harrisoutdoorgroup.com/specialweapons.html). Mr. Crist called his cartridge the 6.5mm Standard Combat Cartridge (6.5 SCC).

Bottom line, if the 6.5 MPC proves reliable in the AR-15/M16 and SOPMOD M4/M4A1 platforms, is combat accurate out to realistic assault rifle engagement distances, and the AR-type upper receivers and barrels hold up to full-auto fire at high round count, then it may just be the ticket for the 5.56's replacement (and thus a better answer than the 6.8 SPC or 6.5 Grendel) for infantry assault rifles and carbines. Time, money, and politics will tell.
If you'd like more info in the 6.5MPC cartridge and weapon conversions (i.e. upper receivers) that are available for it, Defense Review suggests that you contact SSK Industries (http://www.sskindustries.com/).


Company Contact Info:
SSK Industries (http://www.sskindustries.com/)
590 Woodvue Lane
Wintersville, Ohio 43953
740-264-0176 Phone
740-264-2257 Fax
sskindust@1st.net (sskindust@1st.net) Email



Related Articles:
KAC 6x35mm PDW Photos in from NDIA Small Arms Symposium 2006 (http://www.defensereview.com/modules.php?name=News&file=article&sid=883)
DefRev Exclusive: KAC Introduces 6mm PDW for Special Operations Applications (http://www.defensereview.com/modules.php?name=News&file=article&sid=878)
M16A5 Concept: A Modular, Multi-Caliber Rifle for Future Infantry Warfighters? (http://www.defensereview.com/modules.php?name=News&file=article&sid=924)
MGI Hydra QCB Modular/Multi-Caliber AR Weapons System for SPECOPS (http://www.defensereview.com/modules.php?name=News&file=article&sid=919)
Ammunition Improvements for 21st Century Mil/LE Urban Operations (http://www.defensereview.com/modules.php?name=News&file=article&sid=803)
Oakley Eyewear: Advanced Ballistic Eye Protection (EyePro) for Tactical Shooting (http://www.defensereview.com/modules.php?name=News&file=article&sid=695) (Article shows photos of DefRev Owner/Editor David Crane handling and/or firing several tactical small arms on the range at SWAT Round-Up 2004, including the the Barrett M468-A1 6.8 SPC subcarbine/SBR.)

DefRev Quick Hits 3 from SHOT Show 2006: And the Hits Keep Comin' (http://www.defensereview.com/modules.php?name=News&file=article&sid=844)
DefRev Quick Hits 2 from SHOT Show 2006: More 'Latest and Greatest' (http://www.defensereview.com/modules.php?name=News&file=article&sid=843)
Noveske Rifleworks Weapons Packages: CQB Barrel Meets 'The Krink' (http://www.defensereview.com/modules.php?name=News&file=article&sid=776)
Custom MSTN Rifles, Carbines and Subcarbines for Mil SPECOPS, SWAT, and PMC's (http://www.defensereview.com/modules.php?name=News&file=article&sid=615)
Remington Arms 6.8mm SPC Light Tactical Rifle (LTR) for LE Tactical Ops (http://www.defensereview.com/modules.php?name=News&file=article&sid=601)
Robinson Armament XCR Multi-Caliber Carbine/Subcarbine for Military SPECOPS/PSD (http://www.defensereview.com/modules.php?name=News&file=article&sid=669)
Barrett M468-A1 Tactical Carbine in 6.8x43mm SPC (Special Purpose Cartridge) (http://www.defensereview.com/modules.php?name=News&file=article&sid=496)
Update: 6.8x43mm SPC SPECOPS Cartridge in Trouble? 6.5 Grendel on the Rise? (http://www.defensereview.com/modules.php?name=News&file=article&sid=600)
Precision Reflex Inc. (PRI) 6.8x43mm REM SPC Upper Receivers (http://www.defensereview.com/modules.php?name=News&file=article&sid=423)
6.8x43mm SPC Cartridge for Urban Warfare CQB and Short-to-Medium-Range Sniping (http://www.defensereview.com/modules.php?name=News&file=article&sid=383)


Relevant Links to 6.5 MPC, 6.8 SPC, and 6.5 Grendel Discussions:

SSK 6.5mm MPC (http://www.strategypage.com/militaryforums/1-9942.aspx) (Strategy Page)
6.5 MPC--Viable Alternative? (http://www.thehighroad.org/showthread.php?t=211771) (TheHighRoad.org)
6.5 MPC (http://63.99.108.76/forums/index.php?showtopic=15175) (Tank-Net.org)

6.5mm Grendel vs. Rem. 6.8mm SPC (http://airbornecombatengineer.typepad.com/airborne_combat_engineer/2004/03/65mm_grendel_ak.html) (Airborne Combat Engineer)


Acronyms:

USSOCOM - United States Special Operations Command
SPC - Special Purpose Cartridge CQBR - Close Quarters Battle Rifle
SAW - Squad Automatic Weapon
LMG - Light Machine Gun
GPMG - General Purpose Machine Gun SBR - Short-Barreled Rifle

http://www.defensereview.com/modules.php?name=News&file=article&sid=970

ShakesFIST
01-04-2007, 12:12 AM
OW! How about some paragraphs. That hurts to look at...

jagermeister
01-04-2007, 12:25 AM
im not even gonna try to read that crap....

ZoneOne
01-04-2007, 12:38 AM
.....lol.....

digrar
01-04-2007, 12:39 AM
This is mildly better, but it appears David Cranes English teacher needs a punch in the neck.


by David Crane
david at defensereview.com Small arms designer/developer J.D. Jones (http://www.sskindustries.com/ssk.htm) of SSK Industries (http://www.sskindustries.com/) has developed what may just prove to be a superior solution to the 6.8x43mm SPC (http://www.defensereview.com/modules.php?name=News&file=article&sid=383) (a.k.a. 6.8 SPC (http://www.defensereview.com/modules.php?name=News&file=article&sid=383)) and/or 6.5 Grendel (http://www.65grendel.com/) (6.5x39mm) cartidges as a replacement for the 5.56x45mm NATO cartridge for U.S. military general infantry and Special Operations (USSOCOM) use. Mr. Jones is calling it the 6.5mm Multi-Purpose Cartridge (http://www.sskindustries.com/6_5mpc.htm) (6.5 MPC (http://www.sskindustries.com/6_5mpc.htm)), and on paper, it looks pretty good.
The 6.5 MPC (http://www.sskindustries.com/6_5mpc.htm) (6.5x45mm) utilizes the standard 5.56x45mm NATO/.223 Rem. case. However, to maximize powder capacity (and thus projectile velocity and ballistic/terminal performance), Mr. Jones (http://www.sskindustries.com/ssk.htm) pushed the case shoulder back a tad and increased the size of the case neck so it would accept a 6.5mm bullet. The result? A 95-grain "SSK Solid" bullet travelling at a muzzle velocity (MV) of approx. 2600 fps out of a 12-inch (12") barrel and approx. 2800 fps out of a 20-inch (20") barrel. So, were' guessing around 2700 fps out of a 16-inch (16") barrel (unconfirmed/unverified). Pretty respectable. Muzzle velocities for the 110-grain Sierra HP version of the 6.5 SPC are 2480 fps (12") and 2731 fps (20"). MVs for the 120-grain "SMK" round are 2220 fps (12") and 2400 fps (20"). 120-grains is the upper limit of bullet weight for this cartridge. Anything above that affords limited ballistic returns. Impact energy (terminal energy) is reportedly 30-50% greater for the 6.5 MPC (http://www.sskindustries.com/6_5mpc.htm) over the 5.56mm NATO, depending on bullet weights and types, while the weapon remains highly controlloble on full-auto. The 6.5 MPC page (http://www.sskindustries.com/6_5mpc.htm) at the SSK Industries website (http://www.sskindustries.com/) mentions that they've fired a 107-grain SMK round at 2400 fps out of a weapon with a 12"-barreled CQBR-type upper receiver and that effective engagement range is 300+ yards. With longer barrels, the distance is increased.
So, why the 6.5 MPC instead of the 6.8 SPC (http://www.defensereview.com/modules.php?name=News&file=article&sid=383)? Ease and cost of conversion (weapons conversion), ammo capacity, and ammo weight (ammo carry capacity at a given load weight). The 6.5 MPC utilizes standard AR-15/M16/M4/M4A1 magazines and bolts, and will function in both the SOPMOD M4/M4A1 Carbine and belt-fed FN M249 SAW/LMG, provided you switch out the barrel(s). No further modification is reportedly necessary. Mag capacity for the 6.5mm MPC is 30 rounds (although you might still want to down-load it to 28, as many do with 5.56mm ammo for reliability purposes). The 6.8mm SPC doesn't stack properly in standard 5.56mm M4/M4A1 mags, and the magazines that have been developed for it limit ammo capacity to 25 rounds, as opposed to 30 rounds, so the 6.8 SPC mags will fit inside current military mag carry pouches. You can also use 5.56 NATO *****per clips to load 6.5 MPC rounds into the mag. At present, there are no 6.8 SPC *****per clips.
6.5 MPC ammo will reportedly feed as reliably as 5.56x45mm NATO ball ammo can utilize standard M27 links (belt links) with no modification, so it will feed reportedly feed reliably through the M249 SAW. You only have to switch the barrel to 6.5mm caliber. Not so with the 6.8 SPC, which would require modification to the M27 link.
The 6.8 SPC cartridge weighs approx. 40% more than the 5.56mm NATO cartridge. That, combined with the fact that 6.8 SPC mags are made of steel instead of aluminum (making the magazine roughly twice as heavy), means that the infantry warfighter or Spec-Operator will be able to carry less rounds of 6.8 SPC vs. 6.5 MPC or 5.56 NATO.
Reported ammo carry capacity breakdown for the various cartridges at the same carry weight (specific weight unkown, and unconfirmed/unverified):
5.56 NATO: 10 x 30-round mags = 300 rounds
6.5 MPC: 9 x 30-round mags = 270 rounds
6.8 SPC: 7 x 25-round mags = 175 rounds

DefenseReview recommends that you read Stan Crist's article on the 6.5mm Multi-Purpose Cartridge (http://www.sskindustries.com/6_5mpc.htm) in the #44 issue of Special Weapons for Military & Police (http://www.harrisoutdoorgroup.com/specialweapons.html) (SWMP (http://www.harrisoutdoorgroup.com/specialweapons.html)) magazine. That issue has a photo of a U.S. Ordnance (http://www.usord.com/) M60E4/MK43 Mod1 Commando (http://www.usord.com/M60E4Comm_USORD.html) "light machine gun series" GPMG (7.62x51mm) on the cover, and the article is titled "SSK 6.5mm MPC: Multi-Purpose Cartridge delivers bet-your-life performance." While SSK Industries Website indicates that they developed the 6.5 MPC round at the behest of one Brian Hormberg (USMC), it should perhaps be noted that Stanley Crist mentions in his article that he wrote about his own idea for a 6.5mm assault rifle cartidge in the #36 Issue of Special Weapons for Military and Police (http://www.harrisoutdoorgroup.com/specialweapons.html). Mr. Crist called his cartridge the 6.5mm Standard Combat Cartridge (6.5 SCC).

Bottom line, if the 6.5 MPC proves reliable in the AR-15/M16 and SOPMOD M4/M4A1 platforms, is combat accurate out to realistic assault rifle engagement distances, and the AR-type upper receivers and barrels hold up to full-auto fire at high round count, then it may just be the ticket for the 5.56's replacement (and thus a better answer than the 6.8 SPC or 6.5 Grendel) for infantry assault rifles and carbines. Time, money, and politics will tell.
If you'd like more info in the 6.5MPC cartridge and weapon conversions (i.e. upper receivers) that are available for it, Defense Review suggests that you contact SSK Industries (http://www.sskindustries.com/).


Company Contact Info:
SSK Industries (http://www.sskindustries.com/)
590 Woodvue Lane
Wintersville, Ohio 43953
740-264-0176 Phone
740-264-2257 Fax
sskindust@1st.net Email



Related Articles:
KAC 6x35mm PDW Photos in from NDIA Small Arms Symposium 2006 (http://www.defensereview.com/modules.php?name=News&file=article&sid=883)
DefRev Exclusive: KAC Introduces 6mm PDW for Special Operations Applications (http://www.defensereview.com/modules.php?name=News&file=article&sid=878)
M16A5 Concept: A Modular, Multi-Caliber Rifle for Future Infantry Warfighters? (http://www.defensereview.com/modules.php?name=News&file=article&sid=924)
MGI Hydra QCB Modular/Multi-Caliber AR Weapons System for SPECOPS (http://www.defensereview.com/modules.php?name=News&file=article&sid=919)
Ammunition Improvements for 21st Century Mil/LE Urban Operations (http://www.defensereview.com/modules.php?name=News&file=article&sid=803)
Oakley Eyewear: Advanced Ballistic Eye Protection (EyePro) for Tactical Shooting (http://www.defensereview.com/modules.php?name=News&file=article&sid=695) (Article shows photos of DefRev Owner/Editor David Crane handling and/or firing several tactical small arms on the range at SWAT Round-Up 2004, including the the Barrett M468-A1 6.8 SPC subcarbine/SBR.)

DefRev Quick Hits 3 from SHOT Show 2006: And the Hits Keep Comin' (http://www.defensereview.com/modules.php?name=News&file=article&sid=844)
DefRev Quick Hits 2 from SHOT Show 2006: More 'Latest and Greatest' (http://www.defensereview.com/modules.php?name=News&file=article&sid=843)
Noveske Rifleworks Weapons Packages: CQB Barrel Meets 'The Krink' (http://www.defensereview.com/modules.php?name=News&file=article&sid=776)
Custom MSTN Rifles, Carbines and Subcarbines for Mil SPECOPS, SWAT, and PMC's (http://www.defensereview.com/modules.php?name=News&file=article&sid=615)
Remington Arms 6.8mm SPC Light Tactical Rifle (LTR) for LE Tactical Ops (http://www.defensereview.com/modules.php?name=News&file=article&sid=601)
Robinson Armament XCR Multi-Caliber Carbine/Subcarbine for Military SPECOPS/PSD (http://www.defensereview.com/modules.php?name=News&file=article&sid=669)
Barrett M468-A1 Tactical Carbine in 6.8x43mm SPC (Special Purpose Cartridge) (http://www.defensereview.com/modules.php?name=News&file=article&sid=496)
Update: 6.8x43mm SPC SPECOPS Cartridge in Trouble? 6.5 Grendel on the Rise? (http://www.defensereview.com/modules.php?name=News&file=article&sid=600)
Precision Reflex Inc. (PRI) 6.8x43mm REM SPC Upper Receivers (http://www.defensereview.com/modules.php?name=News&file=article&sid=423)
6.8x43mm SPC Cartridge for Urban Warfare CQB and Short-to-Medium-Range Sniping (http://www.defensereview.com/modules.php?name=News&file=article&sid=383)


Relevant Links to 6.5 MPC, 6.8 SPC, and 6.5 Grendel Discussions:

SSK 6.5mm MPC (http://www.strategypage.com/militaryforums/1-9942.aspx) (Strategy Page)
6.5 MPC--Viable Alternative? (http://www.thehighroad.org/showthread.php?t=211771) (TheHighRoad.org)
6.5 MPC (http://63.99.108.76/forums/index.php?showtopic=15175) (Tank-Net.org)

6.5mm Grendel vs. Rem. 6.8mm SPC (http://airbornecombatengineer.typepad.com/airborne_combat_engineer/2004/03/65mm_grendel_ak.html) (Airborne Combat Engineer)


Acronyms:

USSOCOM - United States Special Operations Command
SPC - Special Purpose Cartridge CQBR - Close Quarters Battle Rifle
SAW - Squad Automatic Weapon
LMG - Light Machine Gun
GPMG - General Purpose Machine Gun SBR - Short-Barreled Rifle

Resurrection
01-04-2007, 12:41 AM
http://en.wikipedia.org/wiki/Typesetting

ZoneOne
01-04-2007, 02:49 AM
It's all about shot placement. There is a reason why we have the 5.56. During WWII there were failure to stop reports about the 30-06, .308, and the 8mm. In the Korean War and in Vietnam it became painfully obvious that the amount of ammo was important. The weight became an issue w/ the round (7.62) soldiers could not effectively carry the amount of ammo they wanted and required. It was also documented that the 7.62 sometimes lacked stopping power. Again it is all about shot placement.

The money that would have to be spent in order to change over is just ridiculous. There has also been reports of troops not being able to get enough ammo of 5.56 and 7.62, now would it be worth it add another caliber into the mix of things?

I find that these "kick ass caliber" arguments come from people motivated to gain money. They are the ones that are producing these rounds or help produce it and they are the ones that keep bringing up the argument

BillySing
01-04-2007, 03:08 AM
It's all about shot placement. There is a reason why we have the 5.56. During WWII there were failure to stop reports about the 30-06, .308, and the 8mm. In the Korean War and in Vietnam it became painfully obvious that the amount of ammo was important. The weight became an issue w/ the round (7.62) soldiers could not effectively carry the amount of ammo they wanted and required. It was also documented that the 7.62 sometimes lacked stopping power. Again it is all about shot placement.

The money that would have to be spent in order to change over is just ridiculous. There has also been reports of troops not being able to get enough ammo of 5.56 and 7.62, now would it be worth it add another caliber into the mix of things?

I find that these "kick ass caliber" arguments come from people motivated to gain money. They are the ones that are producing these rounds or help produce it and they are the ones that keep bringing up the argument


Damn Straight. You could chamber an assault rifle in bloody .45-70 and you'd still get reports of poor stopping power. It's inevitable that shot placement will suffer in combat when troops are shooting under stress.

I've killed fallow bucks with a .223 (don't try that at home) with a single shot. It is certainly capable of stopping something.

StukaJr
01-04-2007, 03:13 AM
So someone made a wildcat based on a .223 and drumming it up the publicity using Defense Review... (I swear, to review something - a reviewer needs to have some first hand expossure to the subject, not just paraphrase the salespitch!)
With improvement in modern propellants, there is actually room in the .223 case for more propellant - so bump the shoulder back... why? And if I got my lingo down - "bumping the shoulder back" like in the article would do squat for increasing case capacity...

I'm lost and bewildered at Defense Review more and more...

ZoneOne
01-04-2007, 03:45 AM
Damn Straight. You could chamber an assault rifle in bloody .45-70 and you'd still get reports of poor stopping power. It's inevitable that shot placement will suffer in combat when troops are shooting under stress.

I've killed fallow bucks with a .223 (don't try that at home) with a single shot. It is certainly capable of stopping something.

You were not using a FMJ. Go to a hunting store and look around, 95% of the ammo there will not be FMJ... why?

Because FMJ's aren't good at killing.(compared to other types, for all you literal bastards out there)

Rules are rules though.

BillySing
01-04-2007, 04:15 AM
I was using FMJ actually.

There was this wounded doe on a mate's property, and all he had was ex-mil F1 ball ammo. So I popped it in the head at about 100m. Dropped it like a sack of spuds.

Buckeye67
01-04-2007, 04:27 AM
It's all about shot placement. There is a reason why we have the 5.56. During WWII there were failure to stop reports about the 30-06, .308, and the 8mm.

I agree with your point that shot placement is what counts (see any thread I've posted in regarding the whole "9mm vs .45" debate).

But do tell about these "failure to stop reports" regarding the '06 and 8mm (and I'm assuming you meant to type .303 instead of .308). Of all the reading about WW2 and all the reading about firearms I've done in the past 20 years or so, I've never ever read anything like that.

Seriously - whisky, tango, foxtrot.

dobrodan
01-04-2007, 06:38 AM
So someone made a wildcat based on a .223 and drumming it up the publicity using Defense Review... (I swear, to review something - a reviewer needs to have some first hand expossure to the subject, not just paraphrase the salespitch!)
With improvement in modern propellants, there is actually room in the .223 case for more propellant - so bump the shoulder back... why? And if I got my lingo down - "bumping the shoulder back" like in the article would do squat for increasing case capacity...

I'm lost and bewildered at Defense Review more and more...

They are not bumping the shoulder back to get more propellant in... They are bumping it back to be able to fit a 6.5mm bullet in there...

kongman
01-04-2007, 06:40 AM
what ever hap to the 6.8mm they where all talking about about a year ago

Zero The Hero
01-04-2007, 07:26 AM
Stopping power aside, how about penetration in building materials and stability in light foliage?

A while back there was a video on the forum in which the army tested the effectiveness of different weapons on building materials like plywood, concrete blocks etc. The results showed that at 50m the 7.62x39 went clean through a light concrete wall whereas the 5.56x45 failed to penetrate even with a burst at the same spot.

Also, while it really doesn't matter in open terrain, the increased bullet mass will improve the stability of the projectile in areas of thick vegetation. A lighter projectile will be more easily deflected off its path by leaves or twigs while heavier bullets will maintain their course thanks to more kinetic energy they carry.

I believe there us a demend for a intermediate cartridge such as the one described above.

maw
01-04-2007, 11:16 AM
what ever hap to the 6.8mm they where all talking about about a year ago

6.8mm isn't an effective long range round.
fwiw, jd jones is probably the most prominant wildcatter. if anyone can come up with a death bullet it's him. back to 6.5mm again, interesting. i wonder what the long range ballistics are like and how they compare to 6.5 grendal.

SMGLee
01-04-2007, 01:07 PM
6.8mm isn't an effective long range round.
fwiw, jd jones is probably the most prominant wildcatter. if anyone can come up with a death bullet it's him. back to 6.5mm again, interesting. i wonder what the long range ballistics are like and how they compare to 6.5 grendal.

6.8SPC is pretty darn effective out to 800m.

6.8 is alive and well, mor enad more manufactures are pumpiong up production on the ammunition and more manufacuture are offering weapon in this caliber. HK will have a piston rifle most likely called the 418 chambered in 6.8.

while at a certain facility, a batch of LMT MRP in CQB-R with 12inch barrel mate with Surefire cans were being prep for over sea duties. it is gaining more acceptance as a special purpose cartridge.

People with the 6.8, 6.5, or what ever they come up with, with the military politics and all, it is very unlikely anything will replace the 5.56 anytime soon. besides, the upgraded 77gr SMK MK262 is doing pretty darn well.

silent hunter, do you work for David? you keep quoting his article.. :)

vajt
01-04-2007, 01:30 PM
I also saw on the Styer website that the AUG A3 will also have a future 6.8mm variant. I guess the big question is will the cost of creating a new caliber round outweigh its benefits?

Especially for countries that are still using the 7.62mm round (like Argentina and their FALs), I wonder if for those countries it's not just better to keep the same caliber but either modify the rifle, to modernize it like the Swedes are doing with their FNC/AK-5 or just opt for a more modern 7.62mm rifle, like the FN SCAR or HK MK417.

-----JT-----

oldsoak
01-04-2007, 01:31 PM
Not sure there is a magic bullet that gives accuracy, range, "stopping power" , low weight, small size and low recoil all in one. IMHO thats asking too much. You can design a cartridge that will work well out to 600m after which you'd swap to to 7.62/.308 or greater by calling in a sniper or turning the gpmg on. Given what I've seen of squaddies on ranges, I dont think theres much point in giving them a round that will reach to distances a lot further than they could identify an enemy at, never mind engage with accurate fire. The current 5.56 round will perform quite adequately in the sort of ranges that you would expect the average soldier to be able to deliver accurate, aimed fire ( assuming you are not firing from a carbine and the enemy isnt wearing body armour ). Shooting through walls is all very well, but in OBUA/MOUT that could mean collateral damage or not being able to engage for fear of hitting your guys who are outflanking the enemy you are tryingto pin down in a building.

StukaJr
01-04-2007, 01:38 PM
They are not bumping the shoulder back to get more propellant in... They are bumping it back to be able to fit a 6.5mm bullet in there...

??

"standard 5.56x45mm NATO/.223 Rem. case. However, to maximize powder capacity (and thus projectile velocity and ballistic/terminal performance), Mr. Jones pushed the case shoulder back a tad and increased the size of the case neck so it would accept a 6.5mm bullet."

That's from the first paragraph of the original article post... Given the author's paraphrasing, he is confusing the feck out of me p-) I understand that the neck is widened to accept a 6.5mm bullet but I'm lost how changing case shape would increase the case capacity...

SMGLee
01-04-2007, 01:49 PM
Anytime, anyone say this is the BEST........hmmm makes you wonder!!

dobrodan
01-04-2007, 02:59 PM
??

"standard 5.56x45mm NATO/.223 Rem. case. However, to maximize powder capacity (and thus projectile velocity and ballistic/terminal performance), Mr. Jones pushed the case shoulder back a tad and increased the size of the case neck so it would accept a 6.5mm bullet."

That's from the first paragraph of the original article post... Given the author's paraphrasing, he is confusing the feck out of me p-) I understand that the neck is widened to accept a 6.5mm bullet but I'm lost how changing case shape would increase the case capacity...

Well, it seems like I didnīt read the article well enough, but who blames me?

A 5.56 bulletīs ogive is typically shorter than a 6.5 bulletīs, and to stay within the given length, the case must be shortened and the shoulder pushed back so that the bullet can be seated properly. I believe the angle of the shoulders on the 6.5MPC is steeper than 5.56 to maximize the internal volume of the case.

ZoneOne
01-04-2007, 05:20 PM
I agree with your point that shot placement is what counts (see any thread I've posted in regarding the whole "9mm vs .45" debate).

But do tell about these "failure to stop reports" regarding the '06 and 8mm (and I'm assuming you meant to type .303 instead of .308). Of all the reading about WW2 and all the reading about firearms I've done in the past 20 years or so, I've never ever read anything like that.

Seriously - whisky, tango, foxtrot.

These reports I spoke of earlier were from people who have been there. They recount improper shot placement and having to fire multiple rounds to get the enemy to drop. Same thing during the Korean War w/ the M1 Garand.

That can happen w/ any caliber.

Oh and yes I meant the .303 but I typed the .308 on accident.

I could search for days and probably wouldn't find anything online that can confirm these reports.

maw
01-04-2007, 05:45 PM
6.8SPC is pretty darn effective out to 800m.

6.8 is alive and well, mor enad more manufactures are pumpiong up production on the ammunition and more manufacuture are offering weapon in this caliber. HK will have a piston rifle most likely called the 418 chambered in 6.8.

while at a certain facility, a batch of LMT MRP in CQB-R with 12inch barrel mate with Surefire cans were being prep for over sea duties. it is gaining more acceptance as a special purpose cartridge.

People with the 6.8, 6.5, or what ever they come up with, with the military politics and all, it is very unlikely anything will replace the 5.56 anytime soon. besides, the upgraded 77gr SMK MK262 is doing pretty darn well.

silent hunter, do you work for David? you keep quoting his article.. :)

i was unaware of this. i'd previously asked wes at mstn and docGKR about the capabilites beyond 500 yards, wes' response was "that's what cas is for". coming from a former Marine i found that comment somewhat unusual.

the scandinavian's have for a long time undertood the killing potential (from a terminal effects perspective) of the 6.5mm round, then the 1,000 yard benchrest community started adopting it because of it's stabilty benefits (cross sectional density etc).

i've fired the 6.5 in various form and i'm sold. supersonic out beyond 1200 yards out of an 18" ar. the 6.8spc had always been sold to me as a cqc out to 400 yard round, why wouldn't you just go with 7.62x39 then? but if it has legs then that's news to me.

SMGLee
01-04-2007, 06:08 PM
i was unaware of this. i'd previously asked wes at mstn and docGKR about the capabilites beyond 500 yards, wes' response was "that's what cas is for". coming from a former Marine i found that comment somewhat unusual.

the scandinavian's have for a long time undertood the killing potential (from a terminal effects perspective) of the 6.5mm round, then the 1,000 yard benchrest community started adopting it because of it's stabilty benefits (cross sectional density etc).

i've fired the 6.5 in various form and i'm sold. supersonic out beyond 1200 yards out of an 18" ar. the 6.8spc had always been sold to me as a cqc out to 400 yard round, why wouldn't you just go with 7.62x39 then? but if it has legs then that's news to me.

both those guys are friends of mine, i have had extensive conversion wioth the good doc over lunch and a few drinks. the 6.8 has legs, just the earlier loading were as promising as was expected. the latest batch of development has push the potential further..

Besides, this is an article on the BEST assault weapon cartridge, so we are not really talking about a long range cartridge.

7.62x39 has great merits only in its soft point can it compete with the 6.8 in terminal effectiveness. 7.62x39 in steel core is only good for penetration.

6.8 is a CQB to mid range cartridge that does a darn fine job as it was initial designed for...

Sniffit
01-04-2007, 06:20 PM
What would be the big advantage with this round compared to the swedish 6.5x55mm?

maw
01-04-2007, 06:28 PM
What would be the big advantage with this round compared to the swedish 6.5x55mm?

with minimal modifications (less than required for 6.5 grendal), it would be compatible with existing military hardware.

maw
01-04-2007, 06:43 PM
both those guys are friends of mine, i have had extensive conversion wioth the good doc over lunch and a few drinks.

that's why i dropped those names on ya.


Besides, this is an article on the BEST assault weapon cartridge, so we are not really talking about a long range cartridge.

idle rant alert!
yeah i've heard that before. but if modern technology can give us a round that do everything why not embrace it. secondly, the us plays world police all around the world in a wide range of environments. sure in counter ambush scenarios in a mout setting the 6.8 would shine, but what if you had to take out a mehdi satcom dish at 900 yards? what if you were then deployed to the mountains of southern stan and had to routinely engage targets at diiferent elevations? a flat shooting efficient round would make the fight easier. if it's going to cqc/mout combat all the way then why not just issue m79's and shotguns? i guess i like having a rifle that can do it all. i don't like having a dozen guns for each eventuality, i'd rather limit the list of guns and instead become intimately familiar with the capabilities and potential of one and then practise, practise, practise.


7.62x39 has great merits only in its soft point can it compete with the 6.8 in terminal effectiveness. 7.62x39 in steel core is only good for penetration.

i hear you on the steel core ammo, but even plain 7.62x39 fmj is a very messy round. i've put meat on the table with it and it delivers. i guerss i'm saying that you don't need the jhp to deliver effective terminal performance with 7.62x39.


6.8 is a CQB to mid range cartridge that does a darn fine job as it was initial designed for...

copy that.

Laworkerbee
01-04-2007, 08:01 PM
But do tell about these "failure to stop reports" regarding the '06 and 8mm (and I'm assuming you meant to type .303 instead of .308). Of all the reading about WW2 and all the reading about firearms I've done in the past 20 years or so, I've never ever read anything like that.

Seriously - whisky, tango, foxtrot.

X2 I can't remember reading of a single case of the '06 or .303 rounds used in the Korean conflict ever having a problem with putting a man down........ever.

StukaJr
01-04-2007, 09:14 PM
X2 I can't remember reading of a single case of the '06 or .303 rounds used in the Korean conflict ever having a problem with putting a man down........ever.

I reckon there were cases of multiple .30-06 failing to put down Moors in Philippines - thus the .45 ACP was brought in to the rescue (sarcasm) :) Korean War anecdotes always bring up the failure of the M1 and M2 carbines and winter "watniki" that Chinese troops wore.

So you back and no Hye-Di-Hooe note? While you were out - my M1A is back at Springfield's receiving lot with a rant note (should have gotten 4 Russian SKS's instead) and 200 prepped .45 cases are waiting for the FedEx truck to bring the bullits... I discovered the new hobby for the 10-day blues p-)

Laworkerbee
01-04-2007, 09:47 PM
I'm back seriously jet lagged, I figure I'll be up and running, ready for drinks by Saturday p-)

And yes many stories abound about the lack of "stopping power" of the M1 Carbine and PPSh in the Korean Winter.

22.5degrees
01-06-2007, 12:06 AM
that's why i dropped those names on ya.



idle rant alert!
yeah i've heard that before. but if modern technology can give us a round that do everything why not embrace it. secondly, the us plays world police all around the world in a wide range of environments. sure in counter ambush scenarios in a mout setting the 6.8 would shine, but what if you had to take out a mehdi satcom dish at 900 yards? what if you were then deployed to the mountains of southern stan and had to routinely engage targets at diiferent elevations? a flat shooting efficient round would make the fight easier. if it's going to cqc/mout combat all the way then why not just issue m79's and shotguns? i guess i like having a rifle that can do it all. i don't like having a dozen guns for each eventuality, i'd rather limit the list of guns and instead become intimately familiar with the capabilities and potential of one and then practise, practise, practise.



i hear you on the steel core ammo, but even plain 7.62x39 fmj is a very messy round. i've put meat on the table with it and it delivers. i guerss i'm saying that you don't need the jhp to deliver effective terminal performance with 7.62x39.



copy that.


Maw,
There is no wonder bullet that can do it all. Ok, there is except the last time we got intel on them was the Kennedy assassination. Those were some serious performing rounds!

On a serious note, your example scenario is far fetched and makes little sense. No unit tasked with eliminating satellite dishes or any other high value target would deploy with "issue" assault rifles where a 900 yard shot was required. That kind of talk is nonsense. All firearms and all tools have their limitations. Knowing the limits of your equipment reduces ones chances of using the wrong tool for the job.

Afghanistan and the rural areas of Iraq are both exceptions in regards to what environment most conflicts will be fought. Urban fighting at ranges inside 300 yards is fast becoming the standard. Apart from the first world war long range engagements from fixed positions in future conflicts were rare. There is no need for a cartridge or rifle that is capable of 800 yard shots as standard issue.

The 7.62x39 catridge with FMJ has poor terminal ballistics. I'm sure someone has the diagram displaying the temporary and permanent wound cavities created by 7.62x39 as well as 5.56x45 and 7.62x51. The 7.62x39 FMJ round produces minimal permanent wound damage when compared to the 5.56 . however, 5.56 does not perform well with barriers(M193 or M855 I'm not sure about the Mk 262 stuff) and most who shoot this round understand that. 5.56 excels at terminal ballistics not barrier penetration. That being said, shot placement is still crucial. If shot placement was of no importance than why would we train or soldiers beyond being capable of 7-10 MOA accuracy?

A good example of terminal ballistics is the LeMas pig shooting videos. Even though the ammo used is nothing special it clearly demonstrates that no catridge in current use is a guaranteed 1 shot stop. There are numerous cases of one shot stops using 25 ACP or .32ACP. Even cases where folks have been shot and stopped with .22 LR. That doesn't mean we should be issuing Ruger 10/22's and 5000 rounds a standard load out to each soldier. It does illustrate the importance of shot placement. As was mentioned earlier, every round has limits and there will always be reports or cases of failures to neutralize. Lets not forget one other crucial piece of information. a lot of these "accounts" are second, third, fourth, etc hand stories with few witnesses and often leave out important facts. We've all heard of stories of US soldiers emptying their M1 carbines into North Korean soldier to no effect. Question is did every round make it to the target? Even without any evidence to prove this claim it is automatically ASSUMED that every round hit its target. A more accurate description of the events would indicate the a soldier emptied his M1 carbine IN THE DIRECTION of a North Korean soldier and APPEARED to have no effect.

22.5

maw
01-07-2007, 02:17 AM
On a serious note, your example scenario is far fetched and makes little sense. No unit tasked with eliminating satellite dishes or any other high value target would deploy with "issue" assault rifles where a 900 yard shot was required. That kind of talk is nonsense. All firearms and all tools have their limitations. Knowing the limits of your equipment reduces ones chances of using the wrong tool for the job.

wes at mstn told me the story about the pmc who shot the mahdi satcom dish, it took him a while but eventually made his mark. it was one of his spr clones.
i know of two guys who have 800+ yards kills with the mk12, one of whom is an active service naval special warfare type, the confirmed kill was actually just over 900 yards. the other is a guy in sf reserve guy in 20th. if you'd like more info i could get you some contact info so that you can tell them that you feel that their experiences are "far fetched" and "nonsense"?

playing world police means you don't get to choose the type of terrain you you're going to be deployed to. one day it could be urban, the next could be jungle, mountains, desert or even arctic. we need a heavier round that can penetrate barriers, drop *****es faster and maintain stability over longer distances. imho, a variation of the proven 6.5mm could do that for us.


The 7.62x39 catridge with FMJ has poor terminal ballistics. I'm sure someone has the diagram displaying the temporary and permanent wound cavities created by 7.62x39 as well as 5.56x45 and 7.62x51. The 7.62x39 FMJ round produces minimal permanent wound damage when compared to the 5.56 . however, 5.56 does not perform well with barriers(M193 or M855 I'm not sure about the Mk 262 stuff) and most who shoot this round understand that. 5.56 excels at terminal ballistics not barrier penetration. That being said, shot placement is still crucial. If shot placement was of no importance than why would we train or soldiers beyond being capable of 7-10 MOA accuracy?

we're going to have to disagree here. i shot a deer here this last season with some federal 124gr fmj (because i could). big bambi dropped and the round left a nice hole. i've also fired the federal fmj into a dead hog's chest cavity and while the cavity wasn't as large as the federal soft tips i wouldn't say there was that much difference, it definately tumbles. i've read a couple of reports from iraq indicating that guys hit with upper torso shots are not recovering. these were rounds that bypassed the armor and came in throught the arm pit.

despite what you say. 7.62x39 (even in fmj) is not a poodle round.

22.5degrees
01-07-2007, 09:20 PM
For starters I never indicated that the 7.62x39 round was useless. I'm merely stating that when compared to the 5.56 round it does NOT provide the terminal effects. obviously your shot on the deer was well placed. I'm not saying the 5.56 provides the option of not placing your shots. The fact is that 5.56 in mil service fragments and/or tumbles providing extensive permanent damage. The 7.62x39 does no such thing. Most rounds tumble, its simple physics. The 7.62 does not fragment and therefore produces a lesser extent of permanent damage.

In reference to your stories from folks who play. I cannot confirm or deny your contacts or their stories. I am not inclined to believe that you are a liar so I will accept them at face value. I understand the circumstances but as you mentioned, these are members of the SF community not your average soldier. To adopt a new catridge at the expense of a small percentage of SF personnel who were obviously under equipped for the mission is ridiculous.

I don't wish to "flame" you but this notion that the SF community operates in an ultra high speed low drag vacuum where no additional or ancillary equipment is available between missions sounds a little too much like "24" and Jack Bauer type crap. I am well aware of situations that would require one to use what is on hand. However, these cases are not the norm. SF generally operate outside the normal circles of operation as it is. I really don't think they need to have approval from their branch of the services to use equipment not otherwise available to the masses.

On a side note, I've heard stories from friends who've also been there and done that. Some with the mil some as contractors. I've heard both positive and negative comments for both the AK and the AR systems. Personal opinions and their associated stories are as varied as the systems available.

If the 5.56 cartridge was such a horrible piece of crap, why has it been in service for over 40 years? Please don't tell me its "politics", that seems to be everyone's excuse. The 5.56 has limitations, I know that, you know that, everyone knows that. There are tasks it isn't ideally suited for. Select a different system or work with what you have. To believe that some new "wonder round" coming out will be capable of everything we want is completely ignorant or simply fantasy. In either case I will be just as happy to embrace a new system as you are...Provided it's an improvement over what's currently available.

22.5

Tony Williams
01-09-2007, 01:36 AM
Terminal effectiveness of the military 7.62x39 depends on the type of FMJ bullet used. The Russian and Chinese rounds are made with a mild steel core for cost reasons, and although quite good for barrier penetration these don't tumble quickly which limits the severity of the wounds they inflict. However, a number of countries used lead-cored FMJ (e.g. the Yugoslavian M67 round) and these have been demonstrated to tumble much faster because they have a more rearward weight distribution.

Terminal effectiveness of the 5.56mm has been controversial for decades. Sometimes it seems devastatingly effective, sometimes it doesn't do the job even when well-placed. Recent research has shown that the angle at which the bullet strikes the target makes a big difference as to whether it tumbles quickly or zips straight through, which presumably accounts for the conflicting assessments.

The 6.8mm was designed to maximise effectiveness out to 300m (and lab tests show it is much better than any 5.56mm loading in terminal effectiveness) but in fact the trajectory and velocity loss are much better than the M855 5.56mm, being comparable with the 77 grain Mk 262, so it's probably good for about 700m in a long-barrelled gun. The 6.5mm Grendel is of course even better in its long-range performance - good enough to replace the 7.62x51 as well as the 5.56mm - but for military use there are issues with its short, stubby shape.

I'm sceptical about the new 6.5mm MPC, because unlike the 6.8mm and 6.5mm Grendel, there is no increase in case capacity over the 5.56mm, and that limits the extra performance which can be extracted from the little case. It may be a better choice than the 5.56mm, but enough better to justify a changeover? No way.

NATO (i.e., the US Army in this case) isn't going to change from the existing ammo unless there are huge advantages to justify all the cost and trouble involved. You won't get such big advantages with any conventional ammo. It is highly probable IMO that the eventual replacement for the 5.56mm and 7.62mm rounds (probably in 2020+) will be plastic-cased telescoped or caseless ammo, which is currently being experimented with and shows the potential to halve the ammo weight. Now that is an improvement worth having. Perhaps then we'll get one intermediate calibre round to replace both existing ones.

Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)

dobrodan
01-09-2007, 02:46 PM
Terminal effectiveness of the military 7.62x39 depends on the type of FMJ bullet used. The Russian and Chinese rounds are made with a mild steel core for cost reasons, and although quite good for barrier penetration these don't tumble quickly which limits the severity of the wounds they inflict. However, a number of countries used lead-cored FMJ (e.g. the Yugoslavian M67 round) and these have been demonstrated to tumble much faster because they have a more rearward weight distribution.

Terminal effectiveness of the 5.56mm has been controversial for decades. Sometimes it seems devastatingly effective, sometimes it doesn't do the job even when well-placed. Recent research has shown that the angle at which the bullet strikes the target makes a big difference as to whether it tumbles quickly or zips straight through, which presumably accounts for the conflicting assessments.

The 6.8mm was designed to maximise effectiveness out to 300m (and lab tests show it is much better than any 5.56mm loading in terminal effectiveness) but in fact the trajectory and velocity loss are much better than the M855 5.56mm, being comparable with the 77 grain Mk 262, so it's probably good for about 700m in a long-barrelled gun. The 6.5mm Grendel is of course even better in its long-range performance - good enough to replace the 7.62x51 as well as the 5.56mm - but for military use there are issues with its short, stubby shape.

I'm sceptical about the new 6.5mm MPC, because unlike the 6.8mm and 6.5mm Grendel, there is no increase in case capacity over the 5.56mm, and that limits the extra performance which can be extracted from the little case. It may be a better choice than the 5.56mm, but enough better to justify a changeover? No way.

NATO (i.e., the US Army in this case) isn't going to change from the existing ammo unless there are huge advantages to justify all the cost and trouble involved. You won't get such big advantages with any conventional ammo. It is highly probable IMO that the eventual replacement for the 5.56mm and 7.62mm rounds (probably in 2020+) will be plastic-cased telescoped or caseless ammo, which is currently being experimented with and shows the potential to halve the ammo weight. Now that is an improvement worth having. Perhaps then we'll get one intermediate calibre round to replace both existing ones.

Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)

While the 6.5 MPC has smaller case-capacity than 5.56, it has a larger piston-area, which will help transform the pressure into more kinetic energy than the 5.56 will do. It also looks like this cartridge will accept higher pressures than the 6.5 Grendel, something which may especially help in shortbarreled weapons... Also, the velocity-numbers does not seem to be very far behind the Grendel...

All in all, I believe the 6.5 MPC could easily outperform 5.56... In my eyes a very promising cartridge...

But, what would happen if the case was fullength, and the OAL were increased so that the bullet could be seated properly, allowing for more case-volume, with a higher pressure than the Grendel?

StukaJr
01-09-2007, 03:04 PM
But, what would happen if the case was fullength, and the OAL were increased so that the bullet could be seated properly, allowing for more case-volume, with a higher pressure than the Grendel?

With longer OAL, the cartridge would need more changes to the weapon design - remind you, that 6.5 MPC touts no replacement to the current weapon systems other than the barrel... (That's according to the article, anyways. I'm expected to believe that current 5.56 mag followers will feed reliably a wider necked cartridge?)... Lengthening the OAL is a no-no since it requires similar parts swap to that of the Grendel or 6.8 SPC - 6.5 MPC supposedly skirts these rounds by offering cartridge upgrade with least modifications to the existing weapon system.

But what you are describing would produce a... .224 Weatherby Magnum? p-)

dobrodan
01-09-2007, 03:29 PM
With longer OAL, the cartridge would need more changes to the weapon design - remind you, that 6.5 MPC touts no replacement to the current weapon systems other than the barrel... (That's according to the article, anyways. I'm expected to believe that current 5.56 mag followers will feed reliably a wider necked cartridge?)... Lengthening the OAL is a no-no since it requires similar parts swap to that of the Grendel or 6.8 SPC - 6.5 MPC supposedly skirts these rounds by offering cartridge upgrade with least modifications to the existing weapon system.

But what you are describing would produce a... .224 Weatherby Magnum? p-)

Sure, it would no longer be 5.56-length, but it should not be too difficult to make a new weapon around it... Or new magazines... Or belts (that would actually be very simple)...

If the requirement for a new NATO round is that it has to be 5.56-length, then, the 5.56 replacement will probably be some kind of laser-weapon...

I like the Grendel though, primarily because of its bullet... Which is also the reason why I like the 6.5 MPC...

vajt
01-09-2007, 03:34 PM
NATO (i.e., the US Army in this case) isn't going to change from the existing ammo unless there are huge advantages to justify all the cost and trouble involved. You won't get such big advantages with any conventional ammo. It is highly probable IMO that the eventual replacement for the 5.56mm and 7.62mm rounds (probably in 2020+) will be plastic-cased telescoped or caseless ammo, which is currently being experimented with and shows the potential to halve the ammo weight. Now that is an improvement worth having. Perhaps then we'll get one intermediate calibre round to replace both existing ones.

Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)

I do agree with Tony, if the costs are really as cheap as they claim, then it may make sense to convert. If not, most armies will prefer to stay with what they have, either 5.56mm or 7.62mm, and wait for the next big leap in ammo, whether plastic-cased, caseless or more exotic such as mini guided rockets (as I believe the US was seriously considering, maybe they still are, for the Future Force 2020 soldier).

-----JT-----

Tony Williams
01-09-2007, 06:51 PM
While the 6.5 MPC has smaller case-capacity than 5.56, it has a larger piston-area, which will help transform the pressure into more kinetic energy than the 5.56 will do.
As a general rule of thumb, there is an approximately linear relationship between calibre and muzzle energy for any given case dimensions. As the 5.56mm develops 1,280 ft lbs, so other things being equal just necking it out to 6.5mm should result in around 1,500 ft lbs. This compares with about 1,800 ft lbs for both the 6.8mm Rem and the 6.5mm Grendel. For the new 6.5mm MPC to get anywhere close to the performance of these it would need to be loaded to much higher pressures.


It also looks like this cartridge will accept higher pressures than the 6.5 Grendel...
Why should it? Increasing pressure significantly above the level of the current military loadings is undesirable because it can lead to the usual problems such as cases sticking in the chamber, primers being pushed back against the firing pin, extra barrel wear etc.


All in all, I believe the 6.5 MPC could easily outperform 5.56... In my eyes a very promising cartridge...
Yes, it should outperform the 5.56mm at short ranges at least, but not by enough to make the changeover worthwhile. On past form, the US Army would want to see something like a 100% improvement in performance to adopt a new cartridge, not c.20%.


But, what would happen if the case was fullength, and the OAL were increased so that the bullet could be seated properly, allowing for more case-volume, with a higher pressure than the Grendel?
Then you would be defeating the object of the exercise, which is to permit a minimum-cost conversion of 5.56mm weapons. It is much cheaper to modify a gun by increasing the width of a cartridge (as with the 6.8mm and 6.5mm Grendel) than it is to increase the overall length (which requires a new action with a longer bolt stroke, longer magazine well etc - it basically requires a new gun). And if you're going to adopt a new gun then there's no reason to stick to the 5.56mm case diameter, which is too small to be ideal.

Within overall 5.56mm cartridge dimensions, I think it would make more sense to neck the case all the way out to 9mm by getting rid of the shoulder. You would then have a choice between a really hard-hitting short-medium range cartridge (which could be given the Russian "APCR" type bullet for dealing with most body armour) or a tungsten-cored APDS for long-range shooting and getting through really tough armour. However, that isn't going to happen either...

Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)

StukaJr
01-09-2007, 08:06 PM
Sure, it would no longer be 5.56-length, but it should not be too difficult to make a new weapon around it... Or new magazines... Or belts (that would actually be very simple)...


Well, I'm sure if such cartridge was to be designed - it would have to compete with 6.8 SPC, Grendel or whatever other cartridge is in the tests to supersede the 5.56... Considering that you are selling the entirely new weapon system to utilize a modified cartridge that's only marginally better but not the best of what's in the queue...

dobrodan
01-10-2007, 05:45 AM
As a general rule of thumb, there is an approximately linear relationship between calibre and muzzle energy for any given case dimensions. As the 5.56mm develops 1,280 ft lbs, so other things being equal just necking it out to 6.5mm should result in around 1,500 ft lbs. This compares with about 1,800 ft lbs for both the 6.8mm Rem and the 6.5mm Grendel. For the new 6.5mm MPC to get anywhere close to the performance of these it would need to be loaded to much higher pressures.


Why should it? Increasing pressure significantly above the level of the current military loadings is undesirable because it can lead to the usual problems such as cases sticking in the chamber, primers being pushed back against the firing pin, extra barrel wear etc.


Yes, it should outperform the 5.56mm at short ranges at least, but not by enough to make the changeover worthwhile. On past form, the US Army would want to see something like a 100% improvement in performance to adopt a new cartridge, not c.20%.


Then you would be defeating the object of the exercise, which is to permit a minimum-cost conversion of 5.56mm weapons. It is much cheaper to modify a gun by increasing the width of a cartridge (as with the 6.8mm and 6.5mm Grendel) than it is to increase the overall length (which requires a new action with a longer bolt stroke, longer magazine well etc - it basically requires a new gun). And if you're going to adopt a new gun then there's no reason to stick to the 5.56mm case diameter, which is too small to be ideal.

Within overall 5.56mm cartridge dimensions, I think it would make more sense to neck the case all the way out to 9mm by getting rid of the shoulder. You would then have a choice between a really hard-hitting short-medium range cartridge (which could be given the Russian "APCR" type bullet for dealing with most body armour) or a tungsten-cored APDS for long-range shooting and getting through really tough armour. However, that isn't going to happen either...

Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)

As the 6.5 MPC is based on the 5.56-cartridge, then at least theoretically, it should be able to cope with the same pressures as 5.56, which is a little bit higher than 6.5 Grendel. Because of the small case-volume, the MPC will , at least according to my understanding, compete closer to the Grendel out of shortbarreled weapons than out of longbarreled weapons...

At least one thing of practical importance for the soldiers compared to Grendel and SPC is that the magazine-capacity could be unaltered withing close to the same dimensions as an 5.56 magazine...

reginhild
01-25-2007, 10:32 AM
The 6.8 SPC and 6.5 MPC offer little gain in energy over the 5.56 loaded with the 77gr SMK (OTM) as used by specops. Trajectories and wind drift show almost no difference as well. The 6.8 SPC 115gr OTM will fragment at lower velocities than the standard 5.56 NATO rounds. The 6.5 MPC works best with rounds under 100gr loosing the high BC 6.5mm advantage and delivering less fragment weight - might as well have a 77gr or 90gr 5.56.

The 6.5 Grendel is the only round that offers overall significant improvement. It has better wind drift and drop. It delivers more energy and it fragments similar to the 6.8 SPC when loaded with the 123gr SMK (OTM).

Here is a chart showing just how much energy difference there is comparing two 6.5 Grendel loads (one as the 100% baseline) with 6.8 SPC, the new 5.8mm Chinese round, 5.56 77gr SMK and 7.62x39 Soviet.

Note: 6.5 Grendel 123 SMK compared to 5.56 77gr SMK is a 55% energy increase at 100m and 115% increase at 600m. 6.8 SPC 115gr OTM only offers 25% over 5.56 at 100m and 4% at 600. Combine the energy delivered with fragmentation weight when striking tissue; 123gr of fragments for 6.5 Grendel, 115gr of fragments for 6.8 SPC, and 77gr or fragments for 5.56 and it is obvious which causes the most damage.

Chart referenced from Wikipedia at: http://en.wikipedia.org/wiki/6.5_Grendel
http://upload.wikimedia.org/wikipedia/en/thumb/7/7c/AssaultRifleCartridgeComparisonChart.PNG/800px-AssaultRifleCartridgeComparisonChart.PNG