I see a lot of posts about ar-10's being over or under gassed and also about lots of people changing buffers. I have a PSA Gen3 PA10 18" 308 with the Geissle SSA-E trigger. I put a Vortex Strike Eagle 5-25x56 on it and shot it for the first time over the weekend. I don't have alot of experience with gas guns so was wondering what you look for to know if the gun is gassed correctly or needs any other changes or adjustments? I shot 40 rounds through it with varying factory ammo and thought the recoil was fair and the accuracy was better than I was expecting. I have components to reload but wanted to get some rounds through it before trying to work up a load. I'm very happy with the gun as is but want to be sure I'm not overlooking something that could cause me problems later down the road. All help or input is appreciated.
AR-10 308 tuning info
- Thread starter AverageDad
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If it isn't broke, there's no need to fix it, I wouldn't do anything except shoot it until an actual issue manifests itself.
Most of PSA's issues on this platform are the results of trying to implement the recoil system as cheaply as possible from the manufacturing standpoint. The gas ports were undersized and the rest of the recoil system was minimally adequate to the task, which means when you've got excellent ammo it works Ok and if you don't then it sucks to be you.
That's also why PSA sells heavier buffer and spring kits, to make money off of components they were too cheap to include to begin with.
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OP
Thanks, I just didn't know if there were signs to look for. I've heard of the bcg hitting the lower but I don't see any signs of that. Really surprised of the accuracy, 3 shot group at 100 yards with fgmm 175's.
Looks like you got yourself a real winner there! That's excellent shooting, and I wouldn't change anything if that result is what is typical of the rifle.
Since you have a Gen 3, they must have worked out their issues. I don't think mine was a Gen anything. It was an early one. Any load over about 2400 fps and I had issues. Changed out buffer tube, buffer and stock to rifle length from carbine length. Problems went away. My gunsmith put an adjustable gas block on his and fixed his problems. I have to full length resize my brass with a small base die to avoid rounds not completely clambering. Had issues with popping primers as well. Could be a head space issue. Haven't shot it much since I changed out buffer. It has always been accurate but it has always been a PITA.
OP
The fgmm 175's shot 2470 fps, the Federal XM80C 149 grain shot 2662 fps and didn't group as well. Below is a 5 shot group at 100 yards. Rounds 3 and 5 are the two above the bullseye. Disregard the random shots on target, they were from sighting in the scope. All three brass was being thrown about 3 to 4 o'clock area with the barrel being 12 o'clock. 
After about a decade of interest in this platform, I have yet to see a 1:10 twist barrel that performs well with less than a 165gr projectile. I'm not saying it doesn't happen, just saying that experience hasn't come about yet. On the other hand, quite a few 1:11.25 twist barrels seem to handle the lower weights pretty well.
Something to consider if you prefer to shoot more cost effective ammo and need to re-barrel in the future.
Ummm, iffin you screw with that gun you need to be tarred and feathered.