Pistol braces for AR10

outrider58 said:

Pretty much all fit onto a milspec buffer tube. I believe AR 10 and AR 15 are same diameter.

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alucard0822 said:

Have to make sure your buffer and tube are compatible. AR10s have about 3/4" more travel than AR15s, so you need a longer tube or shorter buffer. Standard 7" AR15 mil-spec tubes (what most SB tactical braces come with) require the small 2.5" AR10 buffer, this is the "DPMS" design. the Armalite setup is a longer 7.75" tube(same as an A5 tube) and standard 3.25" H3 buffer. Unlike receiver sets, you can use the IMO superior A5/Armalite long tube/std buffer in either DPMS or AR pattern rifles. Problem is with LOP, depending on your trigger, most AR10 receivers are about 3/4" longer between the trigger pin and buffer retainer, and can increase LOP by 1/2-3/4" compared to an AR15, then add in 3/4" from an A5 tube, and that nice legal SBA3 that has a 12.5LOP on an AR15 now has a potential NFA violating 14" LOP on an AR10(the longer SBA4 is 13.5" on an AR15). There is some debate, but current opinion is that a LOP longer than 13.5" may be an NFA violation and the "brace" may be considered a "stock", so you may need to use limiters to block the last position or two on the buffer tube.

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CaptPrice said:

That’s very useful info, thanks. I am unsure whether or not I want to build a .308 pistol. That definitely complicates it.

I also have read that .308s tend to overgas with suppressors. I wanted to build a pistol and suppress it for hunting, so I wouldn’t have to pay extra for the SBR.


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alucard0822 said:

Tuning an AR10 is different than it's little brother, definitely use an adjustable block, and IMO an H3 buffer in an A5 tube is the best carbine setup for reliability over a large range of conditions. There is such a huge range of port pressures you have to adjust for ammo and suppressor changes. I generally run mine wide open with Wolf, and it barely runs without a can, with a can it's fine. Most M80 or mil-specish runs well closed a couple clicks, and maybe 3 or 4 clicks more on my SA block when adding the can. There is little excess recoil or gas if I run the can without changing from the unsuppressed setting with 7.62 NATO spec ammo. Some hotter/slower burning commercial 308 ammo needs to be choked off quite a bit more, especially when suppressed, although heavier buffers help smooth it out, and make it more forgiving if you run a couple clicks too much gas.

Use an SBA4, probably the most comfortable and solid brace out now, then add limiters so that when measured in a straight line from the trigger to rear of the brace, you are under 13.5". The 13.5" thing came from private ATF communications with manufacturers, and currently is kind of a grey area, there was a prosecution where the guy walked because the ATF hasn't publicly stated a LOP for braces, but he still had to defend himself in court.

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