The dented shells are not too uncommon for a semiauto rifle. My 742occasionally puts a slight dent in the shell depending on the load and where the shell is thrown.

What bigbulls says about having a gunsmith check over the internals is right on the money. The 740s and 742s will eventually batter themselves to death, and often are not worth repairing.

Another lesson here - - you can't miss fast enough to bag an animal. If your first shot doesn't go where you want it to, the next several are even less likely to, no matter what type of rifle you are shooting with. I finally got rid of a Ruger M77 MkII .30-06 because no matter what I did it would not shoot consistently (not trashing all Rugers, just the one I had.) I now have a few other rifles that will put the first shot where I want it very predictably provided I do my part.

My 742 has NEVER shot so consistently that I would be confident of any shot over 100 yards. For short range work such as hunting hogs in the shrubbery it is great, but if the shot is over 100 yards I won't take it with that rifle.

Just my 2 cents worth... sounds like you're starting to have some doubts about that 740, no?