I have the failures with a wide variety of 147 grain ammo. I tried without the can and still had a failure. I did not try to get a good sample to see if it happened more often with the can than without.
Another thread suggested these causes:
Most likely culprets in no particular order:
Extractor spring
extractor
bolt head (Is it in spec/oversixed? does it pass the zip tie test?)
ejector (is there much side to side play?)
trigger housing (is it parallel to the receiver or is the rear of the housing higher/lower creating an angle?)
The extractor and spring seem pretty solid. They get a good grip on the case. Too good, maybe?
I couldn't find the zip tie test, not sure how to test the bolt head.
The ejector does move side to side if I wiggle it with a finger.
The trigger housing is definitely NOT parallel to the receiver. Here's a pic showing a definite tilt:
A new trigger pack is a little spendy. Is this unusual? Is it so obviously the problem that trying cheaper parts first is pointless? Thanks for any suggestions.
edit: I think I'll pick up a used trigger pack housing, genuine surplus HK, and move my trigger parts over to it.