Interesting M4 carbine barrel length

[DE_Six]

This carbine is manufactured by Troy Ind. as the Advisor carbine. It looks like a monolithic upper, a la LMT. What's interesting is the barrel. It looks like it has the step-cut groove of the M-4 barrel, but is shorter, say, maybe 12.5" plus the flash hider.


http://www.uws.com/TROY/IMG/Advisor.jpeg

Never saw that barrel length before.

[Uncle Sam]

There are soooo many variants to the M4, who knows what will come next.

[pettifogger]

It is an uninterrupted rail like the LMT Monolithic Rail Platform (MRP) or the KAC URX (Uninterrupted Rail Extension), but it is definitely a separate piece from the receiver. In fact, the forend itself is three pieces, but it still free-floats around the barrel. It's the Troy Industries Modular Rail Forend (MRF). Militarymoron wrote a review (http://www.militarymorons.com/weapons/weapons.1.html#mrfc). He also discusses the Troy muzzle and suppressor. The barrel on the CQB-SPCA4 is 13" without the flash suppressor. I don't know of any other AR-15/M16 variant that uses a 13-inch barrel. The midlength MRF-MX is used.

[SKD_Tactical]

Troy has made 12.5" barrels to work with their suppressor collars. It leaves enough room for their collar to thread on without hitting the gas block. The barrel pictured was made just long enough for the M203 barrel mount to attach. The MRF is one of the nicest FF rail systems on the market today, but it wont be able to sustain the weight and recoil of the M203 without attaching to the barrel (as pictured). The LMT MRP can handle the weight and recoil of the LMT rail-mounted M203.
:D

[sergey31]

The above picture is probably just an illusion.

The barrel is about 16", but with a grenade launcher it seems to be shorter.
Take away launcher and it would look like any regular M4

[pettifogger]

No, it's a 12.5"-barrel as stated previously. Notice where the step-cut for the M203 is. That is a standardized length to allow for mounting the M203. Also note that it's a Troy MRF-MX which is 10" long. You can count the number of rails or look at the length of the Tangodown rail cover to identify it as a MRF-MX.

[sergey31]

Extra rails cover up barrel.... Normaly those rails should not be there.

[SKD_Tactical]

http://www.colt.com/law/images/m203_m4.jpg
This should clear things up.
:hug:

[pettifogger]

The standard RIS and RAS units are 7" long. The MRF-MX is longer than a standard handguard.