Re: Ross rifle
There are some who say it never happened or that it can't happen. But I have a Model 1910 Ross and I have put the bolt together wrong (deliberately) and gotten it to fire a primer with the bolt lugs unlocked. It is not very easy to do, but it could be done by mistake.
Properly assembled, the Ross 1910 is one of the strongest rifles made. I once used that rifle to fire up some Italian 7.7 machinegun ammo (same dimensionally as the .303 British) that had destroyed a Mk III SMLE. The Ross didn't care.