I was shooting double action. I will clean the firing pin area better, thanks, I hadn't thought of that. Both times this occurred it was after over 100 rounds, so it is possible it was getting a bit dirty.
Please note that yesterday's occurrence happened with a 3 month old gun, so I doubt it has anything to do with springs. I have a 78 year old S&W that hasn't had any springs changed and it shoots great. Also, neither of my guns ever had a problem with any factory ammo.
Thanks for all the suggestions though!
