I didn't know the difference either. Thanks for the tip! :?SOFMatchstaff said:In general usage the LOP is the measurement from the butt to the trigger face. the length the trigger moves is the "travel", the movement after the sear breaks is the "overtravel", this added to the take up or "slack" would be the total movement of the trigger bar from initial start of pull to the stop at the end of movement. This amounts to about .100+- on my guns. The buttstock extentions that have been offered would extend the LOP.