Set Trigger Problem

[Cotton52]

I’m having a problem with the triggers or lock on the flintlock I’m building. If I fire it with the regular trigger the lock functions normally but if I set the rear trigger and fire the lock it catches in the 1/2 cock position. Nothing seems to be binding or contacting the stock and I have the main spring tightened down. Any advice will be greatly appreciated! Cotton

 

[Phil Coffins]

Is there a fly in the tumbler? If it’s missing or not working properly then catching in half cock will happen.

 

[Tom A Hawk]

Yep, missing fly.

 

[Cotton52]

The fly is in place and moves freely, I even cleaned out the lube I’d used and just went with light gun oil, no change???????
Cotton

 

[Tom A Hawk]

Can you take a close up photo of the assembled lock? Also, the position of the installed trigger.

 

[TDM]

Photos would be a big help, especially the trigger assembly. You stated you had the main spring tightened down. If your referring to the set trigger spring, you may have too tight.

 

[Ames]

Back off the lock bolt 1/4 turn. See what happens.

 

[TDM]

Back off the lock bolt 1/4 turn. See what happens.

That could very well be the problem.

 

[SDSmlf]

The fly is in place and moves freely, I even cleaned out the lube I’d used and just went with light gun oil, no change???????
Cotton

As others have suggested, some clear closeup photographs will help in figuring out the issue.

From your description it sounds like an issue with the lock’s fly. The fly is there so the sear doesn’t catch the half cock notch on the tumbler after the sear bar has been momentarily ‘popped’ by the rear trigger after the set trigger releases the sear from the full cock notch on the tumbler. When you only use the front trigger the fly isn’t needed as your trigger finger will hold the front trigger against the sear bar long enough to allow the half cock notch in the tumbler to pass over the sear.

Photographs of your lock and trigger should help.

 

[Pete G]

Some detents (Fly) can be installed backwards.

 

[TDM]

Having the fly backwards on an L&R lock will certainly cause that problem!

 

[nchawkeye]

Do a search, this was discussed about 2 weeks ago, fix was simple....

 

[longcruise]

Check the bridle screws. If they loosen it can cause this sort of problem.

 

[rich pierce]

Good advice above. In addition:
1)The spring powering the rear trigger causing it to fly upwards could be weak. It can usually be made to give more force by tightening the screw that holds it in place.

2) The inlet for the trigger may not allow the rear trigger to fly upwards enough. To check this fire the set trigger with the lock out of the gun and look in the sear arm hole.

 

[Snooterpup]

The first thing to do is zero in on where the problem lies. The procedure below will help to determine where the issue exists.
Remove the lock from the stock. Will it work out of the gun? If not, the issue is in the lock. Overtightened or too loose bridle screw, or sear screw or fly issue.
If the lock functions outside of the gun, reinstall the lock and remove the trigger assembly.
Now cock the lock and push on the sear with a screwdriver from the trigger group inlet. If the lock works, turn your attention to the trigger assembly. If it does not work, you probably have interference from wood with an inletting issue (not deep enough of rubbing). If it is a trigger group issue, try adjusting the set screw, try shimming the trigger group with card stock to see if it will work. If so,
the trigger may be too high. Others will be able to help with trigger adjustments on set trigger issues. PM me with any questions.
Snooterpup

 

[Phil Coffins]

To test the lock outside the gun the sear must be tapped rather then pressed. Pressing the sear will hold it off the tumbler for that millisecond as it moves past the half cock notch. The set trigger gives a single tap to the sear then the fly must keep it from catching the half cock notch. If you can hold the hammer and disengage the sear then slowly lower the hammer a bit to clear the full cock notch then relax the sear so it rides the tumbler. Continue to lower the hammer fully and it should ride over the fly and half cock till fully down. This will let you know if the lock is working correctly.
Teaching gun smithing is difficult over the internet but we want to help.

 

[Cotton52]

To test the lock outside the gun the sear must be tapped rather then pressed. Pressing the sear will hold it off the tumbler for that millisecond as it moves past the half cock notch. The set trigger gives a single tap to the sear then the fly must keep it from catching the half cock notch. If you can hold the hammer and disengage the sear then slowly lower the hammer a bit to clear the full cock notch then relax the sear so it rides the tumbler. Continue to lower the hammer fully and it should ride over the fly and half cock till fully down. This will let you know if the lock is working correctly.
Teaching gun smithing is difficult over the internet but we want to help.

Thanks for the information Phil, when I actuated the sear the way you said to the edge of the sear hits the fly and digs in like a chisel. Either the angle on the edge of the sear is to sharp or the angle on the edge of the fly is incorrect. The fly also feels very soft when I went to blend the gouge in it out, I may “Case Harden it. Thanks again for the info!! Cotton

 

[Phil Coffins]

The edge of the sear should be sharp, I’d call it crisp. The fly as you figured out needs to be hard.