Hello all! I bought a PSA complete AR10 lower, PSA 6.5 BCG, Criterion 22” barrel, PSA stripped upper, rifle length gas tube and a low profile gas block. I put it all together and came out with a great rifle that I have taken out to 870 yds.
My problem is when I load the mag, I often (60%) get the next round jammed into the spent casing bfore it can eject. The spent round is badly deformed when it is slammed into the chamber by the new round while partially extracted. If I load one round and fire, it ejects cleanly. I removed the gas system and reseated everything to ensure the block was lined up with the hole in the barrel and am still getting the same behavior. Have tried two different factory loads, 140 gr Norma and 143 gr. Hornady ELD-x. Tried two different magpul mags.
This is my first build, so I am hoping one of you expert builders can point me to an obvious place to further troubleshoot. Is the PSA stock buffer weight, spring and tube optimal for 6.5? Any ideas??
If the BCG locks back on the last round and the round is still in the rifle it is most likely an extractor/ejector issue. Since you didn’t specify if your gas block is adjustable or not ill assume it’s not, which means it’s acting like a fully opened gas block. So the issue may be an undersized gas port on the barrel if the BCG isn’t locking back.
Easiest……1st step to diagnose the trouble is using a smart phone to video
the rifle while it’s being fired.
Use the “Slow-Mo” mode and video it from side, from top and video it from receiver to gas block.
Slow-Mo video will reveal :
if the bolt is not traveling reward enough.
If it’s not ejecting.
You can see if gas is leaking from anywhere along the gas system….or verify that the gas is operating efficiently.
Have someone video it while you fire the rifle. The video will surprisingly reveal much about what is happening…making your diagnosis easy.
Thanks for the response. With one round in the mag, it ejects the casing cleanly at about 4 o clock and the bolt locks. With multiple rounds, it is a crap shoot on whether the spent casing will eject fully before the bolt slams the next round into the chamber, more often than not, it slams it into the partially ejected casing.
I’m running a PA65 gen 3 complete lower and took out the buffer and spring. The buffer is 2.5 in long amd has the PSA logo etched on the face, but no “PA10” like on the PA10 buffer listed for sale. Could this be the wrong buffer? an AR15 buffer? Spring measures 11.25 in.
Great idea on the slo mo video. Someone on a 6.5 CM FB group suggested cutting the spring one coil at a time, then test to slow the cycling down and or a heavier buffer. I will definitely make use of the slo mo as a diagnostic tool moving forward.
I regularly have guys bring me guns that won’t operate.
If its not immediately obvious what is wrong……I slow-mo video the operation of the gun. You can see everything….short stroking, not ejecting, gas leaks at the gas block…insufficient gas pressure at the bolt carrier……I find it’s the easiest way to start diagnosing the problem.
The weight should be the same. A fully open gas block should work with almost any buffer weight. Yours may be too overgassed depending on gas port size as well.Check the rim of the case, if there’s a mark from the extractor it typically means it’s overgassed. It’s not unusual for large caliber ARs to extract too hard an leave the casing in the receiver.
I had similar problems with an Aero Precision with a 24 inch barrel.
Took me 2 years to make it work.
The trick was giving it enough gas.
The Hodgdon Reloading loads did not work for me until I only used Magnum (slow burning powders) which generate a lot of Gas.
The faster burning powders (for a 6.5 CM) like 4064 just did not work for me. Even 4320 didn’t work. You use lower weights of the faster burning powders or it is a problem.
Anyway, I ended up using 4350, 4831, and 7828, and similar Alliant powders, and from then on it cycled normally.
Also if you are not using a headspace gauge, you should use one. LE Wilson or Lyman, not Hornady.
Well undergassing may be at least a part of my issue. I’m a noob builder and discovered this evening I’ve been mounting my gas block incorrectly. I centered left to right, but then pushed it back all the way against the ridge on the barrel. Following a post in another forum, I mic’ed the distance from the barrel’s gas port to the ridge, then the distance from the gas blocks oort to the edge of the block. I discovered I was mounting the block .080” too far back. Made the correction and will get to the range this week to see the effect.
I had the same issue on a palmetto state armory upper in 6.5 creedmoor ,it was one of the first ones psa sold and l sent it back to psa and they installed an adjustable gas block on.it. lt seems like l did some more adjusting to the gas block to get it to work.
Hopefully, it’s something easy like gas block alignment. If you still have problems check your gas rings and make sure they are sealing well inside the carrier. Move the bolt back and forth with your fingers it should be sort of stiff. If it has a one piece McFarland gas ring those can create problems by not sealing very well. Also, your buffer can create the problems you’re having. Using a 8 inch buffer tube with a 3.25" (same size as AR15) buffer (H2 or H3) will greatly improve function. Isn’t rifle building fun, lol, keep at it you’ll figure it out.
If this troubleshooting doesnt fix it. This can be brought into our repairs department to be inspected under our warranty. Just reach out to our Customer Service Department and tell them whats going on. They will provide you with a shipping label and instructions on how to send it in to us. Our repair team will look over it and fix any issues with our parts.
So realigning the gas block solved most of my issue. got to the range today and ran 4 10 rd mags. Had three failures to eject toward the end. Pulled the bolt, lubed everything liberally and ran my last 10 rounds flawlessly. In the process, I got my scope rezeroed on a newly installed 20MOA base. I am a happy camper! Thanks for all the help! The slo mo video was a great troubleshooting tool I will remember and pass on in the future!
Just found this thread and find it interesting that I am having a similar problem. I have a factory built PA10 6.5 Creedmoor Gen3 as issued from PSA and have had constant trouble with jamming that seems to be an ejection issue. The rifle has a 5 click adjustable gas block, after some online research, I tried to work up incrementally from fully closed to wide open but never found a sweet spot that worked. PSA recommended a gas setting of 16 clicks which worked for 10 rounds, but after that it went back to the same old problem. I tried adjusting from 12 clicks up to 19 clicks which is when I ran out of ammo with the last round just laying on top of the magazine follower with the BCG locked back. I informed PSA of my results but haven’t heard anything back yet. The bolt in this rifle does show tooling chatter marks that I have not seen any other bolt.
This looks very familiar to what I’m experiencing with my brand new PSA AR-10 308. I’ll try adjusting the gas block to see if that helps and I’ll video in slow mo before and after each adjustment.
