LR308 Part 11 Test Firing the 308 Winchester and 6.5 Creedmoor

I finally got some time to take the LR308 (AR10) to the range. I didn't get the opportunity to test many types of ammo, but I got all three upper receivers zeroed.
The 6.5 Creedmoor was the first one on the bench. Every time I fired it, the rifle would eject the spent case, but not lock to the rear on the empty magazine. At some point, I swapped out the lower receivers to test if the Rifle-length buffer system was too heavy for the build. The failures continued to occur.
I Moved onto the 308 Winchester upper and the first 2 rounds fired and the bolt locked to the rear. The bolt did not lock to the rear when I fired round three. This suggested that I was not getting enough gas through the gas system.
I moved onto the stock Palmetto State Armory upper receiver. I have never had any problems with this upper. This upper didn't fail me. It cycled as it was supposed to. This ruled out the buffer system being the problem with the cycling issue.
I measured the gas ports in the barrels and found that they were a little small for twenty-inch barrels. I decided to drill out the gas ports. The operation went smoothly.
Back on the range, I tested both uppers and they both functioned flawlessly. I inspected the 6.5 Creedmoor brass and found signs of overpressure. Overpressure wasn't a possibility with the ammunition being the same and the gas port being larger. The opposite was true.
I did some research and found someone who suggested that an over-gassed system could cause the signs of overpressure that I was experiencing. I dialed down the gas block and test-fired the upper. The results were good.
This has been a good experience for me. I look forward to testing out different factory loads for both uppers. The one-inch groups these upper receivers are producing, with low-quality ammo, were surprising. I can only imagine what they will do with match-grade ammunition.
If you enjoyed this video, please check out my other videos in this series, Budget LR308 precision build.