Why 2x? I went twice today. Duh.
A load that the 16" runs fine popped a primer in the 8.5" 300 BLK. Ejector marks on that case, ruined it. Other primers looked flat. Reduced the load, runs fine in the 8.5 other than slightly flattening the primers. But, in the 16" gun the reduced load doesn't lock back. Damn you, timing and gas tube lengths. Tried an H2 buffer* and it seemed to tame the pistol on supersonic factory loads.
Also broke out a Mosin today. That is all, no problems with it, hits the target even without the bayonet attached (Sacrilege! I know)
Found an H3 locally, took it down and made an H1 and H2 buffer from another spare.