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View Full Version : m4 muzzle velocity, whats the real value



sowannab
02-23-2005, 12:25 AM
okay i just wanna know someone really knows whats the real muzzle veloctiy of the m4, stock and sopmod
if been searching this thing up for a while now and get a wide variety of answers from 884m/s to 902m/s to 948m/s

has anyone really tested this on a proper range or lab ect.?
just really wanna know
also has does anyone know the fastest muzzle velocity ever recorded for a m4 sopmod or mod?

pettifogger
02-23-2005, 12:55 AM
First, factors other than the rifle determine the muzzle velocity, such as the specific ammunition used. For example, M193 is 3,165fps at 78 feet from a 20" M16, while M855 is 3,00fps at 78 feet from the muzzle of a M16. Temperature and atmospheric pressure can also affect velocity. The same rifle will have different muzzle velocity a few thousand feet up in the Andes than at sea level in Panama.

Second, the SOPMOD package doesn't change the basic M4. An ACOG, M203, or Rail Interface System, isn't going to affect the muzzle velocity. Only thing in the SOPMOD package that would affect velocity is the sound suppressor.

Since a M4 is by definition has a 14.5" 1:7 barrel, there won't be any significant difference between M4s. Barrel length is the primary factor in muzzle velocity other than ammunition. There are wacky things like the ArmsTech Compak-16, but you asked specifically about the M4.

sowannab
02-23-2005, 09:09 PM
thanks
don't know real much about guns
but the m16 is stronger than the m4 due to the barrel length. so what would be the stock colt m4 muzzle velocity with m193 round? or m855?

pettifogger
02-23-2005, 09:42 PM
With a 20" barrel, a cartridge fired from a M16 will have a higher muzzle velocity, than if fired from a M4 with a 14.5" barrel. M193 fired from a M4 has a muzzle velocity of about 3050fps and M855 fired from a M4 has a muzzle velocity of about 2900fps. M193 fired from a 11.5" barrel will have a muzzle velocity of about 2900fps and M855 will have a muzzle velocity of about 2700fps.

M193 and M855 bullets need to traveling at 2,700 fps or more to reliably fragment in human flesh. M855 fired from a M16 would slow down to 2,700fps after about 150m. However, in a M4, M855 slows down to 2,700fps only after about 50m. Hence, many people have expressed concern over the M4's ability to incapacitate, particularly over significant distances.

dacanadianbomb
02-24-2005, 02:01 AM
^^^^^

Very good to the point answer. If I could rate the post Id give it a 10 .

The simplest answer to the "once every two months question about M4/5,56mm power deficiency"

If you know what I mean.

sowannab
02-24-2005, 07:56 AM
what measurements are the barrels? cm/inches?
thanks alot guys i'm just interested about wanting to know about guns.
so the main factor of muzzle velocity is barrel and ammo!
thanks for some clarity.

eggroll
02-24-2005, 09:52 AM
in inches

20" for an M16A2
14.5 for an M4/A1

while you can get fairly consistent velocity performance using GI spec ammo (ie. Lake city, IMI etc.) When you consider civilian ammo, this is when the fun really starts with a variety of powder loads, projectile weights.

consider lemas BMT rounds, ostensibly developed to giver a longer punch to the 556.

keep in mind a longer barrel will translate to faster muzzle velocities, thus commensurate range increases, so conversely shorter barrels will impart shorter effective range due to the premature end of the propulsive force behind the round.

you see these are the tradeoffs that designers, planners, and the to a certain extent the snuffy on the ground will have to make. do I want a lighter more compact weapon with range capability A or do I want a heavier, slightly more bulkier weapon with range capability B at the expense of manueverability, load carriage ability?


EGG

sowannab
02-25-2005, 08:48 AM
thanks all
any you guys know good websites about ammo/rifle muzzle velocity and info?
also is the m4 and m4a1 the same rifle but the m4 only having a burst mode?

pettifogger
02-25-2005, 10:19 AM
The M4 and M4A1 are the same except the M4 is capable of three-round burst while the M4A1 has fully automatic capability.

shrek
02-25-2005, 01:35 PM
We refer to the M4A1 as the SF version.


Good round for what it's designed for

scrybe
02-25-2005, 02:05 PM
In the civilian market BATF requires that the barrel on an M4 be atleast 16" overall. So, if it has a 14.5" barrel, the manufacturer permanently attatches (welds) a 1.5" muzzle break or flash suppressor to make up for the extra length.

Many are made with 16" barrels with a threaded tip, so flash suppressors can be switched out and changed by the owner with simple tools, no gunsmithing required. This extra 1.5" of barrel doesn't increase the FPS by much, but it raises it enough to increase the range of fragmentation quite a bit.

sowannab
02-25-2005, 10:29 PM
is the m193 round good for the m4a1?
also do the us sf use the m193 or the m855 round?

pettifogger
02-25-2005, 10:49 PM
The M4 and M4A1 have a 1:7 twist barrel, meaning that the rifling makes one complete revolution every seven inches. It is meant to be used with the 62 grain M855 ammunition, though 55 grain M193 ammunition can be used at a slight loss to accuracy. M855 is the standard ammunition for all American forces, though the 77 grain Mk 262 ammunition is quite popular with the US Marine Corps and USSOCOM.

sowannab
02-25-2005, 11:09 PM
The M4 and M4A1 have a 1:7 twist barrel, meaning that the rifling makes one complete revolution every seven inches. It is meant to be used with the 62 grain M855 ammunition, though 55 grain M193 ammunition can be used at a slight loss to accuracy. M855 is the standard ammunition for all American forces, though the 77 grain Mk 262 ammunition is quite popular with the US Marine Corps and USSOCOM.
thanks man
so the mk 262 round can be used with the m4a1 also? crazy
isn't the mk 262 an explosive round?

pettifogger
02-26-2005, 01:16 AM
The Mk262 is a open-tip match bullet. Nothing explosive about it, other than it should expand in flesh like other hollowpoint bullets.

dacanadianbomb
02-26-2005, 05:52 AM
Since pettifogger is being so friendly to asnwer a few questions then I would like to throw one in there too :-)

So if the 1/7 twist was made to be used for the M855/M193 round, would the Mk 262 benefit performance wise if the twist was changed ?

And the question is , would the performance increase be large enough to warrant a twist change .

Frens
02-26-2005, 09:19 AM
Since pettifogger is being so friendly to asnwer a few questions then I would like to throw one in there too :-)

So if the 1/7 twist was made to be used for the M855/M193 round, would the Mk 262 benefit performance wise if the twist was changed ?

And the question is , would the performance increase be large enough to warrant a twist change .

1/7 was designed for tracers rounds

sowannab
02-26-2005, 10:00 AM
The Mk262 is a open-tip match bullet. Nothing explosive about it, other than it should expand in flesh like other hollowpoint bullets.
but can the mk262 round be used with a m4a1?
since the mk262 round was made for the spr

pettifogger
02-26-2005, 11:48 AM
As pointed out, 1/7 is specifically to stabilize the longer M856 tracer bullet. M855 works in 1/9 barrels just fine.

The Mk262 was meant to be used in existing weapons without any changes. It's meant to be used in 1/7 barrels. However, it's not recommended to use it in slower-twist barrels such as 1/9. The Mk 262 is routinely used in much shorter weapons such as the 10.5" CQBR and 14.5" M4A1, since it has much better terminal ballistic performance.

For M16 ammunition questions, I really suggest reading the The Ammo Oracle (http://www.ammo-oracle.com/).

sowannab
02-26-2005, 09:29 PM
thanks

@pettifogger
do you know any more websites about the mk262 round used in the m4a1 and ballistics results such as range and muzzle velocity?

i read the info on the website and answered a lot of my questions, it seems that m855 vs m193 argument has been going on a while now.

also does anyone know any websites about sound suppressors and muzzle velocity effects? so what would be the muzzle velocity of m4a1 with a qd suppressor with m855 or mk262 round if that is possible?

thanks alot people

pettifogger
02-26-2005, 10:32 PM
The muzzle velocity of Mk 262 Mod 0 from the 14.5" barrel of a M4 is 2,680fps.

sowannab
02-27-2005, 01:11 AM
The muzzle velocity of Mk 262 Mod 0 from the 14.5" barrel of a M4 is 2,680fps.
thanks heaps
do you any good websites about suppressors and ballistics results on weapons of them?