Lock not holding full cock

[Cap Warner]

I'm building my second gun and have a situation that I didn't encounter with my first rifle.  I've inlet my lock mortise but, when I put the completed lock in place, I can't hold full cock.  Half cock is fine but when I pull back my Large Siler, it snaps back almost immediatley...Is it possible that I pulled out too much wood?  Not sure what gives here...Could really use some expert advice or comment.  Thanks all - I love this forum...

Cap Warner

[smylee grouch]

Almost sounds like you need to open up the sear hole a tad. If the sear hole is too small the sear gets held up by the wood and it wont go into full cock position. If I read your post corectly this might help.  Smylee

[bgf]

Agree about sear hole.  Also check that mainspring has adequate clearance for full cock, especially near the tumbler.  You can probably check by cocking lock, then inserting into mortise to see if it fits.  Doubt you pulled out too much wood, maybe not enough, though.  Another possibility is that the trigger bar may be too high and pushing on sear, also?  You'll get it, just keep debugging.

[coutios]

Agree with Smylee and bgf... Clean up the mortise re-blacken the lock. install and cycle.. Remove and closley inspect for tell tail marks... Remove tha wood... The foot of the tumbler may be interfearing also, not fully completing its rotation into full cock.. Go slow you'll get it.. Are the triggers installed yet???

Regards
Dave

[Captchee]

take your lock out and bring it to fill cock . take note of the distance from the  sear arm to edge of the  bottom edge of the lock plate  when the sear is in the full cock notch.
 now put the sear at 1/2 cock and while watching  the sear , slowly bring the  lock to full . this time take note of how low the sear is  in relation to the lock plate ,just before it drops into the full cock notch..
 
With some locks this  distance is near 0 . Thus the sear hole must  be  very close to = the  edge of the lock plate . If you have that now , then use some inletting black on the sear bar .  Place the lock into the stock and  tighten the lock bolt . Work the lock a couple times then remove it .
 Look for any transfer  of the inletting black  to the  bottom of the sear hole .
 Also one place that’s very hard to see , but often gets missed is the very back of the sear hole . If your working on a precarve OR you drilled the hole with a  standard  drill bit . Remember  the back of the hole will not be flat . its counter sunk .  As such  your lock may fit fine . But when you try and bring the lock to full cock , the sear will hang because the inside , back  of the sear hole  is not square , its tapered . IE deeper in the very center , tapering back just like the end of your drill bit or the plunge router head used by the stock duplicator

[mjm46@bellsouth.net]

Important to use your inletting black here. Black everything it's easy to overlook the little part that's binding, and you won't see it without black. Don't go chopping out wood that isn't marked you'll just be making the mortise too big. Little chips and lots of fitting. Good luck and be patient.

[Dphariss]

I'm building my second gun and have a situation that I didn't encounter with my first rifle.  I've inlet my lock mortise but, when I put the completed lock in place, I can't hold full cock.  Half cock is fine but when I pull back my Large Siler, it snaps back almost immediatley...Is it possible that I pulled out too much wood?  Not sure what gives here...Could really use some expert advice or comment.  Thanks all - I love this forum...

Cap Warner

Brush the sear AND sear spring with inletting black and then install the lock and cock it a few times. Carefully remove the contact points and try again.

Dan

[blunderbuss]

A single trigger has alittle play in it for the sear to be able work. If there is not a little play, the trigger plate could be to high and not allowing the full cock to engage. Or there is a gremlin in it bent on mischief

[smshea]

Not sure from your post if the trigger is in yet but either way, blacken all of the inners of the lock and install it. Cycle the lock a few times and gently remove the lock, as stated earlier pay specific attention to the area around the main spring and the sear hole. Check the sides of the hole as well as the depth of the hole. Make sure you have the bolts tight as you would on the finished product otherwise your chasing your tail. You want all of this worked out before you start setting up your trigger(s).  Look close...something in there will show contact marks.

[coutios]

  As I mentioned earlier I beleive the problem is inside the mortise however there is a longshot that the cock is draging on the side panel preventing it from falling into fullcock....

Well it could happen...

Regards
Dave

[Curt Larsen]

I can't believe this could happen with a Chambers-built large Siler, but if all else fails with the above good advice, maybe the sear spring is too weak and won't engage the sear properly in full cock.

[Dphariss]

I can't believe this could happen with a Chambers-built large Siler, but if all else fails with the above good advice, maybe the sear spring is too weak and won't engage the sear properly in full cock.

Apparently the lock works out of the gun. So the problem is in the installation.
Its wood bound or the trigger is bearing on the sear when it should not. The lower leg of the sear spring may be wood bound.
Is the trigger(s) loose with the lock installed?

The bridal may be pressing on the sear and binding it due to a shallow inlet.
So lock parts need to be brushed with a light coat of black and then installed and cocked a few times.
This will show the problem and a slight amount of wood can be removed.

Dan

[keweenaw]

I had this on a recent rifle, the arch on the end of the mainspring was just barely touching mortise at the top.  Lock worked fine when I inlet it but when the the summer humidity hit things changed minutely.  Wood is touching something somewhere.


Tom

[mjm46@bellsouth.net]

If you haven't trimmed down the stock profile, be sure to check the top of the stock where the hammer may bear on the top of the stock.

[Hawken62_flint]

I didn't see whether or not your triggers are in place, but if it or they are in place, it could be too high keeping your sear from engaging in the full cock notch.  In which case, you will need to file some off the top of the trigger. Otherwise, as all the others have said, take it slow and easy.  The lock I just fitted was a real bear and when I was finished and had the bolster and pan hard against the barrel and the lock bolts tightened, it went to full cock OK and the triggers worked fine, but the frizzen wouldn't close.  It was then I realized the my lock panel was too thick and I had to remove a bunch of wood to allow the frizzen to work.  It just takes time, so just like everyone else advised, take it slow and remove minute pieces of wood till it works.