I'm putting an SBR together, I have no clue which buffer spring to get. I have a 12" rail so I was looking into the faxon gunner 11.5". Which I'm not sure about because it's a 1:8 and I usually see 1:7 recommended.

Are you using a suppressor? Adjustable gas block?

I'm guessing I will be using an adjustable gas block, suppressor later on (I have it ordered).

1:8 is preferable to 1:7.  
The mil uses 1:7 because of the very long tracer round.

Assuming a collapsible stock.
Use a standard carbine spring and at least an H buffer.
I usually go with the H2 buffer on the 10-12" 5.56 uppers.

You could buy an H2, or even H3, and easily swap out the weights with a standard (and cheap) CAR buffer to tailor the weight to what you need.

Thanks for the response.

I run regular carbine spring and buffer with suppressor and adjustable gas.

If you have an adjustable gas block then I'd go with a carbine buffer, and just tone down the gas to the lowest workable setting.

Something else to note, unless you're using a linear Comp (or a stupidly long FH/brake), a 12" rail is most likely not going to work with an 11.5" barrel.  At least part of the muzzle device will end up underneath the handguard which can be problematic.

I like Sprinco and Damage Industries enhanced springs.  Service life is far longer than your barrel will last.

lol yes tracking that's the look I was going for

https://www.aimsurplus.com/product.aspx?item=XAIMB556023M&name=AIM+.223%2f5.56+QPQ+11.5IN.+CARBINE+LENGTH+AR+Barrel+w%2f+Gas+Block&groupid=6479

Any thoughts on this barrel? different port size and twist

Thats what I was going for

I checked out spring co but was quickly confused with all of the different types

Are you going to use a linear comp?  Because if not, this has been known to happen......




Another thing to look at is the ID of your handguard.  If you're really looking at a suppressor in the future, most handguards will not fit a suppressor underneath.

Just get standard weight springs. You can go a little heavier if you want, both should work fine.

Damage only offers standard weight springs.

I have the enhanced gen 2 handguard from Aero. 1.72 clearance, my can is 1.5

I have the same  barrel. I now have an SLR block, but had no issues with a non-adjustable. I went from an H2 to a JP captured spring. Both had zero issues.... make sure your muzzle ports clear the rail, unless your running a linear comp.

Standard carbine buffer, standard spring, standard carbine buffer tube length.

Don't solve over gassing with springs and weights as bandaids... cut the excess gas with port size or adjustable gas block.

The 1/7 barrel you posted is a generic barrel. It should be fine. Remember, faster twist rates ALWAYS equal less accuracy. Use the minimum twist rate that will accomplish your goal. Sometimes you need a longer bullet to accomish your goal and need a fast twist. A 1/8 will run everything you would ever care to. 1/7 is milspec. The only advantage to the slightly higher twist is longer stability in the transonic range before accuracy shits the bed. The trade off is less accuracy till you get there by increasing sensitivity to jacket thickness consistency. None of that is an issue for most 11.5" barrel roles.

That 11.5" barrel will likely be so inaccurate relative to lost accuracy due to twist rate you'd never notice anyway.

ANY barrel that you might desire for high level accuracy will always come with a fitted bolt. If not, it is not a real precision piece. Get what suits your desired role.

Check out the VLTOR A5 buffer system. It is what I run on my SBRs. It makes for a very smooth and forgiving shooting experience across a variety of setups.