M4 SOCOM barrel?

[ejewels]

Hello,

So I was at a local shop recently where they had a SOCOM M4 upper for NFA use only. I believe it was 14.5 inches? The guy said it was an actual military upper/barrel for an M4. I then asked if the Colt AR's (6920) were the same besides being longer lengths, and he said No. He said the military barrels are heavier duty for full auto use. Whats the deal with this? I assumed colt made all the M4 barrels in line and just cut them accordingly.

[m1ajunkie]

The socom profile is a heavier barrel under the handguard than a standard m4 contour barrel. Not sure of actual numbers, but I would say just a couple ounces heavier in weight.

I am pretty sure the "improved" barrels being used on the m4a1 rifles are what people refer to as socom profile.

I just swapped my colt 6920 over to a 14.5" socom barrel and love it. I am running a pinned aac blackout and the shorter length is nice, but either way I feel they are good barrels.

[Mr. Goodtimes]

The retard behind the counter was wrong. The Colt 6920 is the same gun (minus full auto and with a 16in barrel). Both the .gov profile barrels and SOCOM barrels are in service. Colt is the sole source provider of the M4 Carbine to the United States military; contrary to what some gun shop commandos may tell you.

[mvician]

https://www.m4carbine.net/showthread.php?t=4656&highlight=socom

[Belmont31R]

The retard behind the counter was wrong. The Colt 6920 is the same gun (minus full auto and with a 16in barrel). Both the .gov profile barrels and SOCOM barrels are in service. Colt is the sole source provider of the M4 Carbine to the United States military; contrary to what some gun shop commandos may tell you.


What the gun store guy told him is accurate.


6920 16" M4 gov profile (commercial)
6920HB 16" M4 SOCOM profile (commercial)
6921 14.5" M4 gov profile (M4- SAFE SEMI BURST)
6921HB 14.5" M4 SOCOM profile (M4A1- SAFE SEMI AUTO)


The HB barrels are there to absorb more heat (full auto).

[ejewels]

Thank for the replies. So basically, the standard M4's with select fire given in the military have heavier duty barrels, and the semi-auto colts for LE and Civvy have lesser duty barrels?

[NongShim]

Thank for the replies. So basically, the standard M4's with select fire given in the military have heavier duty barrels, and the semi-auto colts for LE and Civvy have lesser duty barrels?

Wrong. M4 has "gov" profile and burst. M4A1 has the SOCOM/heavy profile and auto, rather than burst. Note the parentheses next to the 6921/6921HB descriptions above your post. M4A1 is what is issued to SOF. Not sure if they have started filtering into non SOF units.

[Belmont31R]

To add to the above post the M4 was for regular Army units. The SOCOM profile (M4A1) was issued to special ops guys. The Army was supposed to start issuing the M4A1 (SOCOM profile barrel w/ auto instead of burst) to regular Army units, too.



That, I think, stems from the Battle of Wanat where failures were reported as the soldiers were expending a lot of rounds very quickly. http://en.wikipedia.org/wiki/Battle_of_Wanat


Its pretty unlikely a regular dude will ever see a difference. I suppose the heavier profile near the chamber will help barrel life by heating up less quickly but at the expense of more weight, and may be slightly more inherently accurate due to increased stiffness. The M4A1 has the heavier barrel because its a full auto, and the extra material will not heat up as fast.


The 6920 is made by the same people using the same steels, and the 6921 uppers are the same things as what goes on military guns. The only real difference is in the lowers and fire control group.

[wolf_walker]

Is it just me or are there a lot of socom barrels floating around lately? I'm even seeing them for sale locally, brand new and usually a couple at a time from individuals.

[mkmckinley]

I would avoid the SOCOM barrel profile personally. It's noticeably heavier and really throws the balance off. Unless you're mounting a 203 or trying to use your M4 like a SAW it's not worth the weight penalty. Noveske's N4 profile is much better especially for semiautomatic applications. The Daniel Defense S2W profiled barrels look interesting as well. Here's what a SOCOM profile barrel looks like under the handguards:
http://i.imgur.com/n0Eii.jpg

[aziator]

All the SOCOM/CJSOTF guys I support run a MK18 upper with the DD barrel, 10.3". They have some 14.5" barrels but those are all laying in a pile in the arms room.

[morbidbattlecry]

Does thinking of the barrel help with accuracy at all? I know Socom wanted a thicker barrel for full auto use, but did it help in the accuracy department at all? I know Molon did a post a while ago showing the M4 socom barrel was pretty accurate but i never seen it compared to a standard M4 barrel.

[Sgt_Gold]

Does thinking of the barrel help with accuracy at all? I know Socom wanted a thicker barrel for full auto use, but did it help in the accuracy department at all? I know Molon did a post a while ago showing the M4 socom barrel was pretty accurate but i never seen it compared to a standard M4 barrel.

All things being equal with barrels of the same length, twist rate, metallurgy, etc, the heavier profile barrel will exhibit less barrel whip and therefore be more accurate using the same ammo.

[samuse]

FWIW (not much) I have a 6920HB cut down to 14.7" with a DD RISII and it is a little heavier than a gov't barrel, but it's still light enough that I don't think it would be uncomfortable to carry around all day.

I'll have a better idea after I do the Redback one class in a couple months...