I’ve had this problem before. I was lowering the resizing die too much and causing the case to bulge. Try rechambering an empty case you’ve already fired to make sure it still chambers and then resize the case that is known to fit. If it doesn’t chamber, obviously need to adjust your sizing die.
This ^^^^^^^
My 30-06 will do this until I get the sizing die just right. I set aside all cases that wont chamber. I then set my sizing die to where they just chamber. I screw the die down a scosh (tech term), resize a couple, try them, adjust accordingly. A scosh can be a tiny turn on the die......
As a matter of practice, I always chamber all my hunting rounds after I size them. More than once I thought I had my die set perfect only to find 1-2 that were really tight or just wouldn't chamber. I'd like to know that tidbit before I have an animal in front of me. Chambering shells tends to spook game
