Hard Trigger Question

[Long Ears]

I have a single trigger issue I need a bit of advice on. I just finished my 5Th Long rifle (all from kits). This is the first single trigger however and have an issue with a trigger you could tow a truck with! It is a Large Siler(Chambers) lock that I have polished every single bearing surface to high gloss. I have bent the sear arm several times and it has got a little better but is still at about 11lbs. at the let off. I am convinced the sear spring is too strong (I think). Short of building a new trigger with a higher pivot point can I thin the width of the sear spring and reduce the tension? I am afraid to try and re-temper the spring. I would need a box full of extra ones before I could get one right. You guys are better than all the books I have read combined. Any advice will be appreciated.

Thanks, Bob

[David Rase]

Bob,  Let me ask a couple of obvious questions.  Does the lock operate fine when it is not in the stock?  Does the sear hit wood anywhere in the inlet?  Does the trigger hit wood anywhere? I would not lighten up the sear spring.  That will mke the gun dangerous.  Is the pivot for the trigger inline with the sear bar and sear pivot?  How far from the sear is the trigger pivot?  I have experienced most of the questions I have ask sometime in my career, either on one of my guns or a friends.  Sometimes the lock will operate fine outside the gun, fine when the lock is set into the inlet, but once the lock bolts are tightend up a bind occurs.  I ask that you do a little trouble shooting and get back with us.  There are a number of things that could be causing the excessive pull.  I am sure more will chime in and ask other questions. 
DMR   

[smallpatch]

Dave is asking the right questions.  If you see that there is no binding... the next issue is where it's pinned.  If you have a copy of "Recreating the American long Rifle", there is a great mathematical explanation of the process.  But here's what it amounts to.  The closer the trigger is to the sear, the lighter the trigger, and the longer the pull.

An ideal pull is approx. 3/8" in front of the sear, pinned as high as possible, and the angle of the trigger blade as close to the same angle as the sear bar to the pivot point. 
I hope that made sense.  Again, the book explains it VERY well.

Hope this helps.

[Dphariss]

I have a single trigger issue I need a bit of advice on. I just finished my 5Th Long rifle (all from kits). This is the first single trigger however and have an issue with a trigger you could tow a truck with! It is a Large Siler(Chambers) lock that I have polished every single bearing surface to high gloss. I have bent the sear arm several times and it has got a little better but is still at about 11lbs. at the let off. I am convinced the sear spring is too strong (I think). Short of building a new trigger with a higher pivot point can I thin the width of the sear spring and reduce the tension? I am afraid to try and re-temper the spring. I would need a box full of extra ones before I could get one right. You guys are better than all the books I have read combined. Any advice will be appreciated.

Thanks, Bob

The sear notch in the tumbler likely has a "hook" that is capturing the sear nose or the notch is angled wrong and the sear has to move the tumbler to clear the notch.
Any trigger job involves  some work on the notch and usually the sear nose.
The sear spring is likely not the problem.
Try pulling the trigger with the cock at rest  or holding it back past the full cock location does the sear move fairly easily when the trigger is pulled? If so then its probably the notch.
But this requires careful stoning to correct or you can end up with a too light trigger pull or a lock that falls out of full cock. Properly done you will have a good pull 3-4 pounds and it will stay in full cock even without sear spring pressure.

Dan

[Don Getz]

Dave and Dan both posed possible solutions.    One question they did not ask was.......what type of trigger do you have in the gun?    Is it pinned thru the trigger plate, or did you pin it high, thru the wood?       Is it the type of trigger that is pinned thru the trigger plate, but with extensions above the plate where it is pinned?   If that is the case, how far is it
from where the trigger is pinned to where it strikes the sear bar of the lock?    These are all variables that will affect how
hard the trigger pulls...............Don

[Eric Krewson]

On my first build I bought a trigger plate with attached trigger from Tip Curtis. The trigger was pinned through the plate. Tip drew a line on the trigger bar were the sear should make contact. I installed this trigger/plate combination and had at least a 10lb trigger.

I trashed this combo and made my own trigger and plate using a formula I found on this site for trigger, pin location and sear contact. I now have a sweet 2.5lb trigger.

[Long Ears]

Great job guys, I been working on it all morning. I found where the trigger contacted the sear was back about 1/2". I guess I got the trigger inlet too far forward. I heated the sear bar and bent it forward and opened up the hole a little. I'm still back a shade over 3/8 but the break is down to about 5lbs. I have got to think about how to get a little more. good lesson. I would love to learn how to stone the tumbler and sear from someone. Some things I am afraid to just dive into. Thanks again for sharing your wealth of knowledge.

Merry Christmas to all, Bob

[Dphariss]

The sear nose needs to be cut to the radius formed off the sear screw. The notch in the tumbler needs just a little different radius so that the sear will not be pushed out by the force of the mainspring or trapped by the angle being too steep.
I did an article on this for the Blackpowder Cartridge News some years back.
With careful work it is possible to get the big old Sharps lock with a good stiff original mainspring down to about 8-10 ounces and still pass a "mallet" test. Once done I shot the rifle a lot and the pull never changed.
Brownells sells a set of ceramic stones in square, 3 square and round. The square and three square work really well. But I need to reorder. Over time I have managed to drop or drop something on and break all but the round and the peices have gotten too short.

Dan

[Dphariss]

One more thing the sear notch needs to hold the sear slightly. If not you can have a pull with creep. If the notch holds the sear right then pressure will build before the sear moves and the sear will then pop out of the notch giving a cleaner break when it does move.
Ideally anyway.

Dan