Today at the range, I began to have trouble w/ one particular magazine (1 of 5). The malfunction was that the #1 bullet sat a little higher and pointed up more than the other magazines.
If I placed the loaded magazine into the rifle w/ the bolt closed, there were no problems. If I placed the magazine into
the rifle w/ the bolt locked back, the bullet would stand up in the magazine.
If I got the first bullet into the chamber, all was well for the rest of the magazine.
A close examination of the offending magazine (on left on all photos) revealed that the spine of the magazine had separated at the top allowing the #1 bullet to ride higher. I don't know if it has cracked or was put together badly. I've gone through 8,000 rounds w/ the 5 magazines--that's about 1,600 rounds for each magazine or 64 complete loads each. I would have thought that they'd lasted longer than that but I guess not.
In retrospect two things come up: this didn't happen until today and it felt a little strange loading that particular magazine about half way through a 550 round day.
It's probably my fault-a fellow shooting next to me was admiring the rifle and I had told him that since I got it back from S&W, I had gone through about 7,979 rounds w/ only a small handful of rounds that did not go bang--no fail to eject, etc. Yep, it's my fault!