The only 2 I've had were an issued M9 at BSG that cracked a locking lug during pre-qual in '05 and with my GP100 when a cracked and expanded .357 casing (American Eagle 158gr) locked my cylinder up. 2 TAPS with a rubber mallet and it was cured.
Signature Space For Rent.
"Just relax. Breath normally. All you should see is the front sight post. Ignore the the target. Wait for the pause between breaths and when you feel good about it...ease the trigger back."
-PMI Sgt. Hopkins, USMC