Ar-15 confusion.

[firebrick43]

After 5 years in the Marine Corp and qualifying expert 3 time I feel I have the ar system down pat.

I dont currently own one as in the desert of California, Kuwait, and Iraq they were jamb o matics and had lousy take down power requiring multiple shots. I do find them extremely accurate and love the a2 sights. They are without peer. If ruger offered a sr7.62 in standard a2 config I would probably buy one. But this is all just background.

So here is the question. I am seeing 11" barrels with 5.5" flash suppressors pinned on to meet the 16" length min. When we landed in Kuwait in Jan of 2003 we were issued m4's. Without getting into function issues(think it was more short gas tube/powder choice) most turned back in their m4's for our original a2's. Losing 4" of barrel turned a 500 yard gun into a ~300 yard gun. We were in the open desert and were pulled out before fallajah. Guys I talked to that participated in more urban combat appreciated the shorter m4 in clearing building and I could see that(I would prefer the shotgun however for that role).

So what is the velocity out of a 11" barrel? Are they even accurate or have power left at 200 yards? Why would anyone want one when it degrades performance so much and they still have the same length overall?

[timspawn]

So what is the velocity out of a 11" barrel? Are they even accurate or have power left at 200 yards? Why would anyone want one when it degrades performance so much and they still have the same length overall?

Yes they are still accurate and will kill a man at that distance. The 11" with the 5.5" flash hider is a legal version of the XM177E2, it just looks cool!

[Jupiter7]

Well the m4's you had were not actually 16" either. The a2's are 20" plus flash hider the m4 is 14.5" plus flash hider. Colt figured out that the sweet spot is 11.5" as velocity degradation becomes intermittently non-linear below that as does reliability(change in dwell time). They are still accurate and still hold to MOA requirements of a service weapon but works best for short and fast, up close and keeps length down when suppressed. I've got a few pinned and welded 16" and I've made hits on steel out to 500 with them. The big change from the A2 would be optics, the aimpoints and ACOGs take a lot of guess work out and make hits to 200 easy. 300yds specifically seems to be the hardest for most folks even though drop from 16" is only about 8".

[danski26]

You are asking questions that have many answers. First, 11" barrel with 5.5" flash suppressors is just for looks or bragging rights. Stupid in my opinion but to each his own i say. Barrel length will always effect velocity and asking if a certain length, 11", is "enough" is a questions with many answers. Enough for what? What projectile? Which projectile weight? Anytime you get into terminal ballistics you are going to have MANY different opinions.

You Ask about the velocity out of an 11" barrel but then give us no parameters. What projectile? What case? What powder? What primer? Which factory load? If you narrow things down for us we can give you some approximations. Remember every barrel and rifle can give different velocities to the same load.

Sorry for giving you more questions....just trying to help

Semper Fi

[JSnover]

Given the 5.56 case is rather small, I can believe 11" is an appropriate barrel length.

[Larry Gibson]

When I was in Iraq ('04 - '05) they kept trying to give me an M4. I said no thanks I'll keep my 'A2. They said; but 1SG, they look cool, are easy to carry and easy to get in and out of the hummer with. I said no thanks but I'll take and M14. That got me a deer in the headlight look so I said no thanks, I'll just keep my 'A2. Really would have preferred the M14 though..........

Larry Gibson

[firebrick43]

Since I have really only shot 10k~ of m855 (some out of a saw) what is the velocity out of a 11" barrel?

Semper Fi

[NC_JEFF]

I've only had experience with the A1 & A2 versions and I def prefer the A2. The Corps was phasing out the A1 in the early 80's but I was never fortunate to get any range time with the A2 until after my enlistment was up. I purchased a pre-ban Colt HBAR A2 2nd hand from a shop nearby and loved ever second of trigger time on it. My biggest mistake was sellin it after the assault weapons ban in the 90's, it did bring a hefty profit tho. I replaced it later with a Bushmaster and the enjoyment picked up right where the Colt left off. I've never tried anything shorter than a 20" barrel, (I've always tried to keep a civilian version of all the weapons I shot in the military), although I'm sure they are perfectly fine weapons. I would love to hear how well the 16" down to the 11" brls shoot, might even talk me into buying one.
I also have a Bushmaster Varmint AR with a 24" brl and a dot scope. It is just as fun as the A2.
Ditto on the M14, I've been looking at an M1A1really hard.

[garym1a2]

Short barrel AR's with long Flash-hiders make no sense to me. My 14.5 inch with a pinned flashhider is a good combo, its short and handy, muzzle flash in not much at night. With a Red dot its not a distance gun, my 20 inch Hbar is a good distance gun. The short AR's make great home defense guns.

[nekshot]

What is an a2? Are these all the same basic lower but differant uppers(as barrel lengths and such)?

[timspawn]

The A2 has round hand guards, elevation and windage adjustable rear sight, reinforced areas on the lower and some other changes.

[danski26]

[danski26]

[danski26]

The preceding chart is compliments of DavidC at AR-15.com

[Gunor]

So, a 11.5" would be a pretty good length for a SBR in the .223...not much fall off from 14.5 to the 11.5", but a fairly good drop to the 10.3".

thanks for the info...I just stumbled into this thread - this helps.

Larry Gibson, I can see him making the change from the trapdoor to the Krag the same way...

geoff in Oregon

[garym1a2]

It would nice to see 16, 18 and 20 added to the mix. If you use the peeps the 20 inch has a nice sight raduis.

[bhn22]

Since minimum barrel lengths are legally required anyway, why not make certain that you have as much functional barrel length as possible? The XM177s looked cool, but they were also noisy.

[firebrick43]

Danski26 thank you for finding that.

I found 2889 for a 16" and 3080 for 20".

Found this chart showing bullet drop at 400 meters.
http://commons.m.wikimedia.org/wiki/...y_M16A2_M4.jpg