I have been having occasional misfires with my handloaded ammunition, maybe 10% requiring a second strike to fire the round. I am using Winchester standard small rifle primers and a load of 14.0 gr. IMR 4227 with a 115 gr. lead bullet. Could this be caused by a weak firing pin spring requiring replacement? Or should I try another brand of primers, ie Remington? Or maybe switch to magnum small rifle primers? Any advice would be appreciated.