~ 12" barrels

[wild_wild_wes]

I never paid attention to the 12" barrel (or is it 12.5").

I know the story of how the 20", 10", 11.5", 14.5", 16" and 18" came to be.

Please explain to me how the 12" came about, and why it has its supporters. Thanks!

[TangoSauce]

12.5'' barrels tend to be reliable with a carbine gas system as well as provide a minimal loss of ballistics making it a good compromise for a SBR length.

[Noodles]

IMO, with the popularization of 300blk, I could not justify a 10" 556 hen an 8" 300blk did everything as good or better for what I wanted it for.

So for me the shortest length is 300blk and that left me with a mid-range-mid-length choice of 12.5". I'd equally go 11.5" if there was a 10" rail or configuration I liked more than an 11" rail.

Better dwell over 10.5", better terminal, negligible length difference, personally the longer rail is prefered, more reliable in my opinion, less gas face when suppressed, etc. If I were to jump 10 years in the future I would expect to see lots of 11-12" 556 guns and very few 7-10"... But I could be completely wrong.

[wild_wild_wes]

300blk is its own thing. I was interested in why a 12" 5.56 barrel would be popular.

[Noodles]

300blk is its own thing. I was interested in why a 12" 5.56 barrel would be popular.

And that's what I said. Blk owns short barrel lengths. 11-12 IMO is the shortest practical length I would choose for 556 ammo.

[Todd.K]

It may be the best compromise between a shorter length and velocity. If I could only have one fighting carbine it would probably be a 12.5".

[no2sc2]

hmmmm

[munch520]

It may be the best compromise between a shorter length and velocity. If I could only have one fighting carbine it would probably be a 12.5".

My thoughts exactly. No idea how it "came to be" but I am more than happy with my 12" barreled SBR. OAL suppressed, velocity, weight, accuracy, etc. I feel it's a perfect balance.

http://i163.photobucket.com/albums/t294/myersma2/0EA50A3A-D0B7-49B2-8FBE-D6A0CDE9BFAA-217-00000012BB130687.jpg
http://i163.photobucket.com/albums/t294/myersma2/11-3-12/IMG_4239a.jpg

[polydeuces]

Between my 16, 12.5 and 11.5 uppers the 12.5 has become the go-to rifle. Indeed perfect - balance, weight, size and hardly tradeoff on accuracy.

[SWATcop556]

I'm a fan for all of the reasons listed above. Longer dwell time for improved reliability, terminal ballistic performance, well balanced with a longer rail yet still beneficial as an SBR.

My 12.5 is my go to gun for work. Hands down one of my favorite setups. 12.5 barrel paired with the Troy 11" rail is money.

[calvin118]

A 12.5" barrel with a standard .063 gas port can be reliable without being overly gassy shooting everything from Tula to full power 5.56 (at least from what I have seen). This has not been my observation with the 11.5".

A lot of people say that 11.5" is a significant step up from 10.5" in terms of dwell time, which translates to improved reliability across a wide variety of ammo choices. From what I have seen, while the 11.5" may be better than the 10.5" in this regard the 12.5" is even better.

I also fail to notice the difference in noise and blast between a 12.5" and a 14.5" barrel when both are equipped with flash hiders. Any shorter and the difference becomes increasingly apparent.

As others have mentioned, the 12.5" occupies what many consider to be the sweet spot between external ballistics and compactness.

Subjectively, I also feel that the 12.5" 'feels' and 'balances' the best. If I could only have one, I too would choose a 12.5".

[jwfuhrman]

Since getting my lower Form 1'd back in 2009 I have had literally 15 different uppers for it, 3 10.5's, 3 11.5's and 4 12.5's.

I have found myself wanting a fixed FSB, but not the short 7in rail a carbine gas has. Enter the BCM Kino. IMO the perfect go to gun. Working on building up some funds to get a Centurion Arms Midlength Cutout rail for it but right now it's a "MOE Carbine" topped with a old beat to shit, not saying how I acquired it, TA01.

[YO_Doc]

I love my 12.5 LMT. I put 960 rounds through it suppressed with only needing to lube it every few hours during a cold and windy class in Colorado. During this class there were zero malfunctions and I was only using 3 different mags.

I'm very happy with this little girl.

Edit/added;
That was with an AAC, M4-2000/8

[nml]

Might have been when reflex cans were popular? Nowadays handguard/rail length can play a factor and obviously you can get an extra inch or two more over a 10.3 or 11.5.