FIXED! It wasn't the bolt, and it wasn't the trigger.

by AaronB, Friday, September 19, 2025, 07:11 (17 days ago) @ AaronB

...it was the Bubba.

Previously I thought I had narrowed this rifle's issue down to the trigger sear. Before I dropped $200 on the Timney replacement unit, however, I decided to do a little diagnostic. The firing pin wasn't dropping all the way, and the visual tell-tale was the cocking indicator, which still left a little bit of its red dot exposed.

The diagnostic was, I would leave the bolt in the action but remove the trigger assembly, and see if the firing pin would drop all the way. So I tried that, and... nothing changed. The view from the underside of the action confirmed that the bolt was almost closed, but not quite.

A close look at the bolt handle confirmed it. This is as far closed as it would go.

So my next step was to check in the bolt lug recesses in the receiver, looking for debris. I sprayed it out with brake cleaner... no dice. Since I was running out of possibilities for the problem, I finally narrowed it down to this:

The kind person who installed the 2-piece Weaver scope mounts for this rifle put the rearmost hole on the front mount all the way through, to make room for the length of the rear machine screw holding that mount on. The tip of that screw was sticking down into the upper bolt lug recess, stopping the lug from turning all the way home, and so preventing the bolt from being fully in battery.

Well, one good Bubba deserves another, so with a pair of pliers and my bench grinder I took about 20 percent of the length of that screw off the tip, and reassembled it. At last success; I was able to successfully pop a primer in a chambered empty case.

Now maybe I can get this rifle zeroed, which was how this business all got started.

-AaronB