I received my Mars 10/22 trigger kit this evening. Put it in a 1980’s vintage factory trigger group. Same vintage factory bolt. Bolt, receiver, and trigger group are what you might call WELL USED. Many thousands of rounds through this old rifle. Left out the bolt hold-open, as recommended in your installation video.
After initial install, I found that the trigger would not function. Trigger wouldn’t move sufficiently to the rear to release the sear. If I pull the front trigger assembly pin out, and pivot the trigger out of its normal position by a millimeter or two, allowing some space between the hammer and bolt, it would function.
I watched the Mars video on adjusting the curved area at the bottom of the safety bar. Started to do as they recommended in that video, and stopped… that bar is riding on top of the hammer bushing, the area that they recommend removing a few microns from is directly over that bushing. I removed the right side bushing and reassembled the trigger. This gives the unit LOTS of room under that curved area of the safety bar, and it had no effect on my issue. Could have removed a quarter inch from that curve, wouldn’t have corrected the issue I was seeing.
Inspecting the unit, using a little white grease to see where things were touching, it appeared to me as if clearance between the bar and the bolt while the bar is fully down isn’t a problem, in my case. It’s clearance on the TOP curved portion, ahead of the flat bolt interface. That bar has to come up to allow the trigger to release the sear, and it can’t. It’s hitting the bottom corner of the bolt. Needs a few thousandths more room.
I removed a few thousandths from this curved area, basically shortening the flat bolt interface a bit by pushing this curve back, making sure it was smooth and flat, and that the curve into the flat bolt interface was perfectly smooth. Polished it a bit with some 400 grit, and re-installed.
Golden.
Excepting jams from the brand new, very tight chamber of the barrel I just put on this rifle, the trigger is working as expected. Ran a box of standard velocity CCI through it, got better and better as I went. I’m expecting it just needs some rounds through it to break in a bit at this point. Probably switch to something a bit hotter, see how that works.
Seems to be a quality product, even if it needed a bit of fitting.
