Speaking of firing pins...
I know of two instances in which a Beretta 92 has accidentally discharged because of a broken firing pin.
Apparently, if the firing pin is broken and the hammer is decocked on a live round, the rear portion of the firing pin will be locked, but the broken portion can be propelled into the primer.
A quick test is to stick a pencil in the barrel of the cocked pistol, decock the weapon, and see if the pencil jumps.
Snap-caps are cheap, and if you can buy a gun and ammo, invest in a couple. Or do what I did, buy a set of them and split it with a buddy. Safe dry-firing is one of the best ways to improve your shooting. I've corrected numerous shooting errors and developed muscle memory through it, all while on a tight budget. It may not teach recoil management, but it can do wonders for grip, sight picture, and trigger press.