The very worst thing a person can do to a mauser trigger is to remove the first stage. If one wants a single stage trigger, an overriding sear type is the best bet. Smooth up the "bumps" with a fine stone, smooth up the bottom of the tang, then spot harden it, then polish. The contact surfaces of the sear and cocking piece should be smooth, hard, and sharp with a neutral contact angle. If the first stage can be pulled to the second stage with about 1 to 1 1/2 lb of pull and will reset when released, it is good. I generally aim for a final let off of 3 pounds or slightly less. If I had a receiver which was as badly grooved as yours, I think I would cut a recess and install a tungsten carbide insert at the wear point. GD
