I've adjusted triggers on a couple Tell 3's with no issues. Possibly your sear piece has worn, or is stuck and not moving as you try to 'heavy up' the engagement? You might try removing the screw and pushing down with a punch to see if any motion happens, then penetrating oil if necessary.
Don R.
It's a long time since I had one apart, but I'm sure mine was a straight headless screw (set-screw in US parlance), with a fine pitch and nothing to prevent removal. It simply presses down on the swinging sear piece to change its amount of engagement with the piston rod. Unlikely but possible that the bottom end of yours has gotten squashed and distorted the thread end. See the last pic' from Danny's Gallery patent drawings:
Don R.
Last edited by draitzer; 11-12-2023 at 07:52 PM.
Yes Don, looks like it should come out. The instructions say that unscrewing gives a more positive engagement and heavier trigger. Will make up a narrow flat screwdriver with larger diameter handle to get better purchase. If I get it out completely will replace with allen head grub screw which is far better.
Baz
BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD