I have done a few, they are just harder to work on the the older triggers. Small Allan headed wrenches, heat is required, ignore the top screw. Little "c" clips very difficult and easy to lose. I can usually get them to (sometimes as low as 2 pounds) usually 2.5 to 3 pounds for $60 for the new style trigger, $40 for old styles. includes return mail. The trigger assembly only is required.