I picked an aftermarket trigger assembly off of evilbay recently....the seller said the safety spring was broken......and yep, it was.....gone, actually. I order one....take the assembly apart and get it fit in there. Fixed that issue. Then, Once the hammer is cocked and the disconnector is partially depressed....I pull the trigger.....nadda...nothing. I'll fast forward a bunch and spare you the 2 1/2 hour trouble shooting session.....The hole drilled for the cross pin on the trigger bar is drilled too far forward and the OAL of the trigger bar is too long to properly engage the sear....WTH? Since these came in white cardboard boxes and not installed on rifles.....I can only assume that these were function checked before being sent out the door?? So I very slowly and gently file down the sear end of the trigger bar to attain the proper clearance and it works great. Changed out some springs in the process. This was my first dive into a trigger assembly and I have to tell ya.....I was intimidated before today....but these things are fairly damn simple and I'm now kicking my own a$$ for not doing this type of work sooner. I'm not adjusting engagement angles or anything crazy yet, but they are pretty fun to work on.....