My one frozen bolt episode was with a Montana, and happened right after we had killed a black bear, chased off a brown bear, and then cut up the black bear and put it in packs. Right at dark, we picked up rifles to discover that my bolt couldn't be moved. Luckily, the other guy (Sitka Deer's kid) had a single shot rifle that was operable.
I had (lightly) lubed the FP threads with eezox, which I blamed for the issue. Who knows if that was accurate or not, but I have been leery of it since, and don't use it on anything internal to the rifle anymore. That was also right about the time that I decided that a pistol doesn't really weigh that much.
