Hi all. Long-time creeper, first-time poster.
I have an Aero M5 .308Win with a 20" barrel. All parts stock except for the stock & trigger. I am starting load development after finally getting my hands on some LR primers, and I am encountering pressure signs (extractor marks) on starting powder loads. Even with the starting load, I will get extractor marks even when the load is too light to cycle the gun properly (i.e. no lock back on last shot, failing to chamber the next round from the mag). Needless to say, vexxing.
A little background on my loads and results:
175g SMK - 41.5g of IMR4064 (listed starting load from Hodgdon) = no lock back, light extractor marks on 2 out of 5 test rounds
175 SMK - 41.7g of IMR 4064 (bumped 0.2g higher to see if I could get good function) = Sub MOA accuracy, lock back on last shot, but failed to strip 1 of 5 rounds off the mag; extractor marks on all rounds, two of which were particular deep and sharp.
Anything I tested higher than this showed OBVIOUS signs of overpressure, so they're not even worth mentioning. At 42g+ I started getting DEEP extractor marks, flattened primers, even a couple of blown primers.
I have been digging into this for some time, and I see many people recommending a JP Enterprise High Pressure bolt. I've also heard an adjustable gas block might do the trick. I have been eyeing an Aero adjustable block that's going for $54. The JP HP bolt is $200+ 😬. I get it, buy once, cry once, and I'd like to grab one eventually, but right now the gas block seems like a more economical solution.
Do y'all think the adjustable gas block will be valuable in solving this problem? Should I just opt for the HP bolt instead? Am I even on the right track with this solution? Any assistance would be appreciated. Thank you.
