Guns: Diagnosing premature slide lockback, or "I'm back to the S&W 642 again"

Although it's less serious than a failure to extract, a failure to feed or fire is still not something you'd want to see in a carry gun. Sometimes rounds will be caught up trying to get into the chamber, but in my case, my P-01's slide stop was locking the slide back prematurely (that is, before the mag was empty). 200 problem-free rounds with my seldom-used 10 round mag convinced me that the culprit was a weak magazine spring.

How could a weak mag spring cause the slide to lock back? If the mag spring is weak enough, rounds can move forward from the mag during firing (basic physics - the gun and mag are moving backward from the recoil, and if the round's not gripped tightly enough, it slips). The nose of the bullet can then trip the slide stop. Almost every magazine spring wears out eventually, most often from the constant loading and unloading the springs have to endure.

A quick order with Wolff gunsprings and hopefully I'll be back in business by the end of the week. This is a good illustration of why it's best to have some unused test magazines for troubleshooting. Another possible cause of a premature lockback is a weak slide stop spring - this part is not so easy to replace on my gun, so I hope the new mag springs fix the problem.