Set Trigger Problems

I have some problems with a custom-made late Lancaster. I cocked the hammer and went to set the rear trigger, it almost set but went I took my finger off if it, the hammer fell. I backed off the screw between the triggers a bit and the rear trigger sets when the hammer is down. If I cock the hammer first, the rear trigger will not set. If I set the rear trigger first, then cock the hammer, everything works. I do not know the make of the triggers. I do not want to pull the trigger set out of the gun if it can be helped. The front trigger will still trip the sear on its own. The center screw is very difficult to turn due to its location and I would like advice before I do anymore adjusting.

Set the rear trigger with the hammer down is how that lock works. There are different types. If it holds half cock after the set, you are all good.

I'll indulge in a bit of speculation here. There is a mainspring on the internal side of the tridder plate that has been over tightened. This spring is lifting the rear trigger lever to the point that the rear lever is interfering with the sear lever. When the triggers are set, the trigger levers are lower, and the nose of the sear fits into the notches in the tumbler. The adjustment requires the trigger group to be removed. That may probably require removal of the pins holding the trigger guard. It's too bad the triggers weren't adjusted by the builder.

I think Mike is on the right track here. Another possibility is that the rear trigger blade should have been filed down some.

To diagnose take the lock out and look in the sear arm hole in the lock inlet and see if the rear trigger blade is well up into the sear arm hole.

If it is, remove the triggers and cut a piece of cereal box cardboard to fit in the trigger inlet at the front and back ( not where the action is). This effectively drops the trigger lower. Re-assemble and see how it works.

If it’s fixed then either live with that spacer or file that cardboard thickness off the top of the rear trigger blade.

Thanks guys. I backed out the adjustment screw a turn and the set trigger now works after the hammer is fully cocked. I am not sure why that worked or if there is something that I should still be concerned about. This was built by a known rifle maker who is no longer with us, so that I would think that he would not have sold it to me with a design flaw. I have never shot it and only tried the set trigger with the hammer down. I guess that he just did not take the time to adjust it.

Rich Pierce not trying to hijack OP,S pjst but does the rear trigger blades need filed down 90 plus percent of time on new builds? Thanks