My AR-15 collection is starting to expand and I am getting into new territory. I just put together a 7.5" pistol and I am curious to what weight of buffer I should be running? I had an extra carbine buffer and spring in the parts drawer so I used those for now. I have not shot it yet so I cannot give a feedback report as the upper is being worked out of state. Is there a certain weight that belongs to certain barrel length’s/gas systems? I will be putting together my first mid-length at the end of this month but I am guessing that a carbine buffer setup will be fine for this? Any suggestions or can someone point me in the right direction?
I bought a PWS MK107 upper, they suggested a H2 buffer.
I may suggest a H3, with it and the std carbine buffer you got you can swap the internal weights and make any buffer weight in between.
Spot on advice there.
I’ve run many setups with spikes st-t2, always works, 300 blackout, 9mm blowback, many different barrel length 5.56’s
I’ve also never had a 7.5"…
What brand is your upper? I know that the Adams Arms 7.5 is designed to be ran with a standard carbine buffer & spring.
All this advise is 100% based off no information that the OP left us with, so it’s only guessing.
Main thing… what brand barrel do you have?
Second… what type of ammo will you be using for the most part? BH 77Grain or…?
Third… what muzzle device do you have on? Are you going to use a kx3 or similar or leave it just with a flash/comp device on there?
Fourth… what type of environment are you going to be shooting in? Extreme cold/cold, or hot? With uber short barrels temperature does effect reliability.
IMO you should get an h,h1,h2 anyways just to have them on hand. Do the lock back test until it fails to lock back, then go to the previous lighter weight one that worked. Play with buffers according to ammo and temp also to see what works for your barrel brand/gas port size. Personally for myself, I just use milspec springs. No reason to do otherwise IMO.
If you want a longer RE, you could always go to the a5 extension and play with that as well.
Correct. Without more info it’s all guesswork. Will it run with an H or H2? Probably so. Is it the best set up? That’s the question.
You’ll be solving a lot of common AR Pistol problems (including those fixed by heavier buffers) by installing an Adjustable Gas Block. You’ll have the flexibility to shoot a very wide range of Ammo, run a cleaner gun, and mitigate recoil.