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Trigger won't stay at full cock

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Buckskinn

45 Cal.
Joined
Dec 12, 2018
Messages
501
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Location
Mukwonago, Wisconsin
For a year and a half all was good, now my double set trigger will not stay on full cock. I assume I had some wood move due to humidity, but wonder why I had no issue last summer. I guess I will have to take it apart and shave a bit more off the rear trigger plate. Anyone else ever have this issue? It was a nice trigger pull and I knew it was a close tolerance, but it was safe...
 
I put a small drop of removable blue thread locker on my trigger adjusting screws for that reason. It jams the threads just enough to stop the movement.
 
For a year and a half all was good, now my double set trigger will not stay on full cock. I assume I had some wood move due to humidity, but wonder why I had no issue last summer. I guess I will have to take it apart and shave a bit more off the rear trigger plate. Anyone else ever have this issue? It was a nice trigger pull and I knew it was a close tolerance, but it was safe...
If you are saying the set trigger won't remain cocked, the little screw between the triggers needs adjustment. Unscrewing it a few turns will increase the engagement of the front triggers catch with the rear triggers latch. That will keep the rear trigger set until the front trigger is pulled.

If you are talking about the lock not staying cocked, that could be due to the trigger assembly moving closer to the lock. That can cause the front triggers blade to keep the locks sear arm from moving down. If that happens, the sear nose won't be able to engage the full cock notch.
Putting a shim or spacer between the underside of the trigger plate and the stock wood at the bottom of the mortise will move the trigger group away from the lock's sear arm and restore the operation to normal.
 
The sear bar and or the tumbler notch may have worn down allowing movement. They do wear. Best to check just to eliminate the possibility.
 
Have you noticed it lately, and not in the winter time? It could be a function of the wood swelling due to humidity
 
I had the same issue with a safe queen of mine. I finally figured out that a few strategic scrapes in my lock mortise resolved the malady
 
Apparently Buckskinis not too worried about it. Hasn’t responded to questions since fi post. We still don’t know if it’s the trigger or lock. Can’t help without input from him.
 
It's not an emergency,,,, but I guess I should have explained better, it is the lock not stayin cocked, double trigger is working correctly.

I'm going to take it apart and see what best solution is.
 
Most likely, @Buckskinn, you will need a shim between the trigger plate and the lock mortise. There is only a small ledge of wood for the lock plate to rest on and after a year and a half of shooting, the lock plate is being pulled deeper into the trigger plate mortise. Over tightening the tang bolt can pull the trigger plate deeper into the mortise as well. The tang bolt is one of the bolts that just needs to be tightened to the level of snug. If you set the trigger, can you set the hammer at full cock? If you can then you need the shim.
 
Something is putting pressure on your sear, keeping it from slipping into the notches on your tumbler.
It can be your trigger, but it can also be wood interference from shrinking/swelling in the lock mortise .
Black the internals, reinstall the lock, and cycle a few times.
Should see marks where wood needs to be removed.
 
I have had this happen a couple of times with my set triggers over the years. In both cases, it was caused by the tightness of the lock plate screws, and was remedied by backing off the torque. Whether this was due to the lock mortise wood compressing over time, the effect of humidity on the wood, or simply my over tightening of the screws, the problem was permanently resolved by backing off on the tightness, just snugged finger tight, while still making sure the lock plate was secure and well mated to the barrel flat. As an aside, this level of torque on the lock plate screws can also effect the ease of ramrod removal with some locks, squeezing the portion of the rod tip that rests just behind the lock mortise. When I adjusted the trigger screw to address the trigger function, ramrod removal was effected when the lock screws were tightened too much. On any of my rifles, I will always check the trigger function and ramrod removal when replacing the lock. Not sure that this is the OP’s issue, but it may be worth a check.
 
So had a little time to play with this thing today. As suggested I loosened the tang bolt slightly as well as the lock plate bolts. When loosening the lock bolts it made an audible relief... This did help as it will now stay cocked, but will set off if I lightly push on hammer. If I set the trigger first, it is just fine. I assume that I will likely need to shim based on comments above?
 
I don't know which gun you have but this was a common problem with the CVA Mountain rifles. Inlet too deep and problem was solved by shimming out the trigger plate like previously mentioned.
 
If the hammer just barely stays cocked one of two things are happeneng. Both of them can keep the sear from fully engaging the full cock notch in the tumbler.

Either the sear arm that sticks out towards the inside of the gun is bottoming out in the clearance hole in the stock or, the trigger plate and the blade on top of the trigger are touching the sear arm, keeping it from moving fully into a engaged position.

If moving the trigger plate improved things, I would remove the trigger plate and then file the top of the blade that is attached to the front trigger down, at least 1/32". That should fix it.
If the sear arm is bottoming out in the clearance hole, use a file and file about 1/16" off of the end of it. Although the nose of the sear is hardened, usually the arm part is left soft so filing it shouldn't be a problem.
 
Smoke the sear bar and rear of the lock in a candle flame and install it in the gun. Work the hammer a couple of times. Then remove the lock and look for the black where the metal is hitting the wood. Cut the black away and do it again until there is clearance. Also look in the hole and see if the end of the sear bar is bottoming out on the far side of the trigger inlet and leaving soot there. Check for trigger bar interference with the sear bar while the lock is out. Clean the soot off the lock and oil the lock.
 
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Well I finally got a chance to work on this. I ended up filing down the sear bar just a smidge and then polishing several levels up to 3000 grit. Worked perfectly! I figured that was easier than pulling trigger... Thanks for the help.
 
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