Ruger M-77 "hang fire" mystery solved.

by Hoot , Diversityville, Liberal-sota, Sunday, September 30, 2012, 21:37 (4383 days ago)

I posted a week ago about a Ruger M-77 in which the firing pin would not drop at the pull of the trigger when the bolt was held down; firing instead with the slightest lift of the bolt.

I putzed with this thing off and on since then trying different things to isolate the problem. Stripped the bolt down as far as possible and cleaned; no change. Swapped a bolt out of another M-77; no conclusive results. Removed the action from the stock and found out a previous owner had installed a Timney trigger. Fiddled around with relieving the stock around the safety bar; no change. Cut the stock opening for the trigger body a bit more; still no change.

The first real break was when I tried backing off the screws for the trigger guard. Backing off the front screw (middle of the three) about 3/4 turn and the firing function returned to normal. The on-line copy of the installation instructions talks of 'relieving the top of the trigger guard' and, sure as Hell, it looked like the guard was jammed up tight to the trigger body. Ten minutes with a hand file provides a "skosh" (an old Norwegian percision measurement) of clearance and proper function to boot.

"Well, huh.", says I.