I've got a pre-war N Frame that has a bit of an issue in DA. SA is perfectly fine, but when cycling DA, right at the beginning of the trigger pull there is a hitch that takes varying degrees of force to overcome. Sometimes the hitch is nearly imperceptible and other times the trigger and hammer get completely hung up in the hand-off and jams.

I think I've narrowed it down to an issue with the sear I believe but I'm not sure if it's an issue of being too short or just some grittiness that keeps it from fully resetting. Since the DA pull seems fine a points and degrades at other times to full jam, perhaps the sear is getting hung up. I have sonic cleaned the hammer and trigger but can do more soaking if needed.

Since I'm a self-taught hobbyist, I just did a bunch of swapping parts to see what happened. First I tried a 455 MK II but those parts didn't work at all (I thought it was only the TL and the 1917 that were drastically different). Then I used an early 30's 1926.

455 MK II action


1926 action


Problem action


The two with their original parts still installed


Where the hang-up or hitch occurs


just the 1926 hammer swapped in


just the 1926 trigger swapped in


Conclusions:
1. Swap in 1926 hammer only - DA is great
2. Swap in 1926 trigger only - worse DA issues, the sear is resting on the trigger and completely binds up nearly every pull.

The difference between the two sears is evident with the smaller curved one being the one with issues. (1926 on the left)




The area on the triggers that engage the sear are different between the two guns with the 1926 being about 0.008(ish) thicker. (1926 on the left)


>>>Is this just a case of replacing the sear and having it fitted to the original trigger or is a new trigger also needed?

Thanks!

The rest of the gun glamour shot