Guess I have never heard of one blowing up!
The only problem I've heard of is not feeding well, but the Montana 1999 action was originally designed for gunsmiths to finish up, as a hybrid of the best features of the 98 Mauser and pre-'64 Model 70. This finishing was supposed to include tuning the feeding for the specific cartridge the rifle was chambered for, but many people just screwed barrels on and expected the action to feed well, no matter the cartridge, as long as the rim fit the bolt face.
I've shot several rifles made on 1999 actions with no problems, all made by gunsmith who knew how to finish up the actions, including my Serengeti Walkabout 7x57, one of my favorite hunting rifles.
