About one in 5 mags has an issue where the round fires, then the case partially ejects, and is sitting perfectly parallel with the port right on top of the incoming round.
I replaced the extractor spring with a Wolff extra power I had laying around, but still happens. 230gr LRN at about 700FPS. It was fine with this formula until about two weeks ago.
Time for a recoil spring? New extractor? IIRC I installed a slightly stronger one when I first bought it two years ago.
Edit: I just checked and I have a 16# recoil spring installed. Should I go back to the 13# it came with?