Building an SBR, I’m leaning towards a 11.5 inch barrel, will an extra inch up to a 12.5 make that much difference? I’ve heard that when you go below 11.5 you start to see more reliability issues, and accuracy is greatly reduced. Will 1 inch + or - make that much difference? Now I know SBR’s aren’t long shot guns, but I would still like to keep some accuracy at distance. I’m new to the SBR world, but not to the AR world.
I have a 10.5in and a 12.5in. My 10.5in is just a standard cut rifled barrel. My build is a Mk18 Mod 1 style build. I use it for 150yd max as after that, you lose to much velocity.
My 12.5in is a BCM SS410 barrel that I built as a “patrol” gun. Running a 1-4x24 optic on it. Retains enough velocity out to 300-350 to be effective with the right ammo(read, NOT FMJ) like 68gr+ OTM or the 64gr Federal TRU or 64gr Winchester PSP Soft Point ammo or you can run 55gr Barnes TSX ammo(but thats exepensive).
“accuracy” is actually not effected by barrel length… there are plenty of 10.5" barrels that are significantly more accurate than a lot of 20" barrels.
but you do lose velocity, which equate to a higher ballistic arch, and generally less terminal performance at ranges beyond 100m, depending on the ammunition.
as far as reliability goes… 10.5s can be finicky, 11.5s generally seem to be less finicky, and 12.5s seems to be real solid performers- in quality barrels mixed with quality parts. but any SBR can be a headache to tune in.
what’s your purpose for the weapon?
Accuracy wont be reduced by going below 11.5" with say a 10.5". The 10.5 is a little harsher on parts but you shouldn’t see any reliability issues with a quality, properly built 10.5" so if you want a short gun, its still a viable option.
Ultimately, define the role that the weapon will serve and things become a bit clearer.
Also read around on the site. There are tons of discussions on SBR barrel lengths.
I was debating between 10.5 and 11.5 for mine. I think I have decided on 11.5 for a little extra punch at slightly further distance
Sorry guys, I guess I was using the term “accuracy” a little loosely, I know that the length of the barrel doesn’t affect accuracy, I guess bullet drop and energy is more what I’m looking for. I’m 60% using it for recreational use, 30% because I want something different, and other 10% because I like making stuff and the mechanical workings of an AR are just damn sexy to me and why the hell not. And as far as other threads on here, I just wanted some fresh opinions. Technology changes every day, and so do opinions.
I have an interest in building an SBR, so subscribing in for interest…
If you shoot someone at 300M with an 11.5" or a 12.5" do you think that they are going to know the difference? Do you think that you will really notice the difference in accuracy between two equal quality barrels? I doubt it.
Reliability issues arise with any SBR if you buy piece of shit guns or components. If you get quality then you won’t have any problems.
Anyone who says otherwise is ignorant.
I will agree that the difference between 11.5 and 12.5 is not going to make that much difference on the target down range. I just prefer the 12.5, you gain slightly more velocity, and with the extra inch reliability goes up even more.
But with 10.5, and maybe Im wrong, I just feel the loss of velocity is to great past 150yds to be AS effective as a 11.5 or 12.5
My suggestion: If you’re going to also use a suppressor I’d recommend a 10.5-11.5", if not I’d recommend the 12.5" it’s a great size and easy to handle gun. Mine has a 11" Troy/VTAC tube on it and a Battlecomp 1.0
@ Robb:
I was looking to build a “Kino” configuration carbine from a BCM upper/lower combination, but I intended to suppress it.
Why do you recommend the 11.5 over the 12.5 for suppressor use?
Is it just for overall length reasons?
Thanks!!
Length. Either will suppress just fine but the 12.5" Kino will be longer than a 16" AR.
Roger that. That’s what I figured.
That’s what I was thinking. I plan on running a suppressor on mine.
I’m using quality parts for this build, not extreme high end, but not cheap either. Mostly bcm, Troy, and spikes. And I’m not sure if I will be putting a suppressor on it right now, but I am planning on putting either the sw556 on it or the BC 2.0, so I atleast have the option later. And how much reliability issues are we talking about with a 11.5 vs. 12.5? I’m willing to live with it if it’s not that big of a deal. I just though of this too, are they anymore ammo picky then any other rifle?
Maybe a Surefire mini can?
Hmm.
You can’t really predict reliability issues based on barrel length, there are too many other factors and no two situations are exactly the same. I have a 10.5 MRP CQB and couldn’t be happier with the performance suppressed or not. I have about 1000 rounds down the pipe, about half suppressed, mostly Wolf 55 gr and it has performed beautifully.
I just ordered a 12.5 for mine. I figured I needed an all around general purpose rifle much more than I needed an ultra compact rig. I’m not clearing any rooms or jumping out of vehicles. 12.5 has plenty of range for civillian needs, including the kind of hunting I would likely be doing (Coyotes and Boar). So, for my needs, a 12.5 5.56 barrel is a good fit.
If I did feel the need from something shorter, 6.8 or .300 BLK are looking pretty good to me.
12.5 is an awesome all-around setup
Well damn, I was kind of all set on an 11.5 but now y’all got me thinking about a 12.5. But I also have a 16" rifle, so if I’m going short, I might as well go 11.5 right? DAMNIT! WHAT TO DO!!