This condition is called firing pin “Follow” and is most often caused by an untimed action. When the bolt moves forward in an un-timed action, the firing pin strikes the trigger sear before the bolt is rotated to the lock position. Striking the sear aggressively can create a dynamic instability inside all triggers which can cause the firing pin to follow. The lighter the pull weight setting on the trigger, the more sensitive the trigger will be to the striking force. Timed actions only contact the sear during the bolt rotation phase, which is much less aggressive than the striking force created by an un-timed action.
Another geometric problem is that the lead-in ramps and the primary extraction are not synchronized but are actually in conflict with one another. Other factors that can contribute to this are:
- Insufficient firing pin and sear overlap.
- Insufficient cocking piece / transfer bar overlap.
- Excessive wear on the rear bridge of the receiver.
- Worn bolt body diameter.
- Geometry inside the trigger is not to spec.
- Tolerance mismatch between sear and cocking piece
If you are experiencing this issue, please contact us. You can also speak with your local gunsmith about timing your action and other possible causes related to your firearm.