09-10-2019, 06:36 PM
"Notice while testing that it didn't lock back on last round a couple times with my handloads. It did better with the oem SST's. Brass is landing 4:30 at 8 to 10 feet with only very small flat spot on the mouth. Removed gas block and cleaned everything in the gas system, block, tube, key, and bolt. Gas port measured .094. Drilled it out to .096 and installed adjustable block. Started with open one round, and went out slowly to wide open before it ever locked back, and then it wasn't consistent. Put the old block and tube back on and it locked back on the oem rounds, but failed to occasionally on my weaker hand loads, but cycled fine."
The above indicates not enough energy in the system.
You could try cleaning the buffer and buffer tube and lube them with a good oil (like synthetic motor oil). Inspection of the buffer and buffer tube may indicate an issue there. Try a different (lighter) buffer? or lighter buffer spring?
Take a good closeup pic of new unfired brass hand cycled and also fired brass (remove carbon with solvent) and post it. Same with the extractor.
There are some excellent pics of what the extractor shape should look like here on the forum and also on Johnny's Reloading bench's Grendel vids.
You will solve this and learn a lot in the process!
The above indicates not enough energy in the system.
You could try cleaning the buffer and buffer tube and lube them with a good oil (like synthetic motor oil). Inspection of the buffer and buffer tube may indicate an issue there. Try a different (lighter) buffer? or lighter buffer spring?
Take a good closeup pic of new unfired brass hand cycled and also fired brass (remove carbon with solvent) and post it. Same with the extractor.
There are some excellent pics of what the extractor shape should look like here on the forum and also on Johnny's Reloading bench's Grendel vids.
You will solve this and learn a lot in the process!