I recently built my first AR pistol. I am fairly new to the ballistic side of things, I usually plink for fun not concerned about the technical aspect of things. I put a PSA upper with an 8.5 inch barrel on a PSA lower. Any recommendations for ammo? I have heard that some lower quality ammo such as TULAMMO may not be a bad idea because of the lower pressures. Would a heavier grain bullet work better? HP or FMJ? Any advice you could give me would be greatly appreciated!

https://imageshack.com/a/img924/295/0D0psY.jpg

Austin

I have a PSA 8.5" pistol and use 55grn HP and soft point ammo.  Rounds still moving fast enough to expand.

I’d feel just fine using some M193 rounds.

M193 certainly isn't going to fragment reliably at those velocities, but it will still put a hole in whatever it is you're shooting

I've had luck with Wolf in the aspect of not being underpowered. It's on par with federal 223 or hotter.

55gr SP is a great choice

Im in the same boat... here is what I have found.... I will list approx. ballistics stats for a 8.5 inch barrel
your best bets are,

62 grain federal Fusion (Muzzle velocity from a 8.5 inch barrel) 2300 fps... expansion threshold 1700 fps or less.
Black Hills 77 grain TMK 2200 fps, expansion threshold 1900 fps or less
Speer GD 64 grain, 2100 fps , expansion threshold 1700 fps or less
speer GD 55 grain 2400 fps, expansion threshold 1700 fps or less
Black hills 50 grain TSX 2600 fps expansion threshold 2300 fps.
Winchester ranger 64 grain BSB 5.56 2300 fps expansion threshold 1600 fps.

The TSX will get you about 75 yds and the others should have enough velocity for expansion at 100 yds or more from an 8.5

MK318 does well out of a 7.5" barrel:
https://youtu.be/FNekOq9CBQA?t=2m41s

Check out his channel, he must have 30+ gel tests of different ammo out of 7.5" barrels.