10.5" vs 11.5"...Practical Knowledge

[INPatriot]

Pistol, SBR, either.

What is the practical difference in a 10.5" 5.56 barrel vs an 11.5" 5.56 barrel?

I've been researching for a couple days. No need for charts, ammo types or statistics. No debate on whether the caliber is suited for either length.

What's the practical difference for individuals that will use these barrel lengths at 25, 50, 75, 100 yards. In short ranges do differences in terminal ballistics (400-500 f/s) matter?

Thanks

 

[ryknoll3]

I went with 11.5" because Paul, the owner of BCM gave a good explanation of why they make a 11.5" barrel instead of 10.5". Basically, it comes down to a better gas system dwell-time, generally giving better reliability.

There's really no practical difference between the two barrel lengths in regards to ballistics, range, accuracy, etc...

The FPS difference is only about 100 FPS, or so. You said 4-500. Are you thinking of a different barrel length? One inch isn't that much different.

 

[esrice]

Paul Buffoni's (BCM) reasoning for the 11.5" barrel swayed many people. And I'm sure his reasoning has merit.

That being said, I don't think it suddenly and completely negated 10.5" guns. I've read many accounts of solid 10.5" SBRs, and some not-so-good.

My 10.5" Noveske runs great and I made several consistent hits at 728 yards yesterday. I'm a fan.

 

[INPatriot]

Some interesting data for the 10.5" vs 11.5" barrel selection process. - AR15.Com Archive

One of the sets of numbers I've been reading.

 

[wsenefeld]

For a practical difference... The 11.5" is very popular with those that live in a state that doesn't allow an SBR as an NFA item or for those that do not wish to register their lower as an SBR. If you put a Gemtech Trek on an 11.5" barrel, it gives you an OAL of 16.2" for your barrel. You then need to silver solder or tac weld the Trek to your barrel to make it "permanently attached." Then you only need 1 stamp instead of 2.

Paul Buffoni's (BCM) reasoning for the 11.5" barrel swayed many people. And I'm sure his reasoning has merit.

Here's that BCM article I think you were refering to. This is what swayed my 10.5 vs 11.5 dilemma.

https://www.ar15.com/forums/t_2_138/174764__Q__Why_BCM_chose_the_11_5_SBR_over_the_10_5_.html

I have a 11.5" Spike's Tactical CHF barrel with an H2 buffer and so far it has eaten everything including brass, steel, and lacquer/poly coated steel. Furthest I've shot it was 400 yards and I was easily able to hit an 8" plate with a Vortex Viper PST 1-4.

It should have a stock on it by the end of summer.

 

[ghostdncr]

The XM177 (Mod 629) I was fortunate enough to work with had an 11.5" barrel and for the most part, functioned flawlessly and performed well downrange. I've been around some of the 10" weapons and have the general impression that they suck mud. That extra 1.5" of barrel apparently makes a huge difference, or at least that's my conclusion based on somewhat limited experience. My next AR build is going to be a semi auto recreation of that old Mod 629 and the 11.5" barrel is a foregone conclusion.

 

[INPatriot]

I appreciate the knowledge a great deal from everyone! One follow up: does the profile of the barrel - lightweight, government, medium, heavy - have an affect on ballistics?

 

[MontereyC6]

I personally own a 10.5" and a 12.5" sbr's. Functionally I can't tell anything different between the 2, both have been 100%. The only thing that I will add to this thread that hasn't been mentioned, is that most suppressor manufactures won't warrant there cans on anything under 11.5".

 

[avboiler11]

AAC's warranty is no shorter than 10", except SDN-6 or SR-7 down to 7.5" with 300BLK or 5.56.

 

[KJQ6945]

I personally own a 10.5" and a 12.5" sbr's. Functionally I can't tell anything different between the 2, both have been 100%. The only thing that I will add to this thread that hasn't been mentioned, is that most suppressor manufactures won't warrant there cans on anything under 11.5".

Correct me if I'm wrong, but I thought most would warranty down to 10.5. I asked this question when I bought my can, because my Colt is 10.3, as are all other "mk18" guns.

 

[KJQ6945]

Esrice, lets put this 10.5 vs 11.5 debate to bed once and for all. I've read so many articles (as most of you have also) that claim one sucks and the other is the only way to go. Lets plan a shootout, I've heard you have access to a range.

Personally, I think the biggest problem for the 10" guns is people building their own and having a hard time dialing them in. Once dialed in by an individual, or the factory, I think the differences boil down to one is an inch and a half shorter.

Plan it and we will come.