I have never had a gun go down as hard as my former LWC in a staged malfunction drill.
Thunder Ranch DHG2 LL 1999. Raining, 100 degrees anyway, 2 in the morning. Lay your gun down in the gravel, let someone you don't know dick it up, run forward, pick it up, engage.
So the merit scholar from Norcross slips my firing pin stop plate down. Tap, rack, stop falls out, fp hits me in the eye pro and disappears in the pitch black on the black gravel.
I dont normally carry a backup, but I carry one at classes now -- so I can shoot the next guy who does that.