put one on mod 70 30-06 made early 70's never fired. smith installed and set at 2.5 lbs. sweet shooter. after 20-30 rds the trigger pull got like HARD to pull. was outta town so took it to another smith he set it at his min of 3 lbs. 20-30 rds later getting harder to pull on again. its my sons and hes coming to visit and am thinking about setting the dam thing myself. causes? are they hard to set/work on? now i wish i could stick a rem 700 trigger in there!! help! THANKS