?Bend sear leg lighten trigger pull

[wet willy]

Just finished a Kentucky/Siler small percussion/maple. Trigger plate too forward, so pull is nice, crisp, but much too heavy. Can't change the placement of the trigger plate or lock, so now what?

Constrained by the lock/trigger placement, but can I do anything to help (also knowing a light, short, crisp trigger is not possible with this geometry).

Polishing sliding surfaces, adjust springs, hone sear nose, etc, will little to address the basic problem.

Could I heat/bend the sear bar back to give more distance from trigger pivot?

Could I modify the trigger blade?

Mac

[Don Getz]

Willy......bending the sear bar might work, but you don't want to bend it "back", or increase the distance from the pivot
point.  If you want to decrease the pull, you should shorten the distance from the pivot point.   You must find that
"happy medium", where the pull is fairly light, and the trigger does not have to move very much.  I have found that if
you place the pin thru the trigger slightly less than 1/2" from the sear bar, it seems to work pretty well.  I also do some
stoning on the sear and notch, merely smoothing them up makes for a better trigger pull........Don

[Mark Elliott]

Make sure you bend it hot (1500 F+) or it will break.   It is possible to do this without loosing the temper in the part of the sear that engages the tumbler.  Just clamp the part with the hole in a heavy vise and very carefully heat the bar at the 90 degree bend.    I had to bend the bar up in my last rifle because it was so thin (the rifle that is) that it couldn't accommodate the triggers I chose to use, even grinding them down substantially.    After getting it adjusted just right,  I did end up completely re-heat treating the sear.   I could have left it as it was, but just didn't feel right doing that on a new rifle.

[smylee grouch]

Is the trigger lever pinned through a post on the trigger plate or into the wood in lock mortice?  You could remove post on trigger plate and replace with one a little farther forward if that is the type of setup you have. Or make a post a litle forward of present  pin location if pinned into the wood.

[Jim Kibler]

How far is the sear contact from the trigger pivot?  How high is the trigger pivot? 

[Dave B]

I think this may be helpful to you. Here is a example of a French fowler that has pivot point that is inline with the line from the sear screw to the sear arm. the distance as you can see is almost half way between the two points. This position gives a crisp light trigger pull.  Sorry for the oblique view which makes the trigger drawing possition look weird but there is no mistake on the pivot point of the trigger.

[cmac]

You can taper the sear spring down: from the bend to where it contacts the sear. I do this on a sharpening stone and it helps with the pull a lot.

[Acer Saccharum]

Warning on messing with the sear spring: if you SHORTEN the leaf at all, the effect of the spring will be stronger, and the harder the trigger pull will be.

The closer the tip of spring is to the pivot, the easier it pulls.

So, thin the spring,if needs be, but don't shorten it.

[RAT]

Three things that can help lighten a trigger pull are...

1. Replace the sear screw: On most commercial locks there is a lot of play between the screw and the hole in the sear. This causes wobble and drag. Start with a larger than normal screw and turn it down so there is no more than .001 undersized from the hole. While you're at it, when you thread the new screw, cut the right number of threads on it. Most of the time the threaded portion is too long. When you tighten the screw it pushes the bridle arm against the sear or sear spring and binds it up.

2. Check the sear spring: Make sure it's not in contact with the bridle arm. If it is, you can remove some material so it no longer touches. As stated above, if you're replacing the spring, it should touch the sear right where the flat part meets the round part around the screw hole.

3. Move the trigger closer to the lock plate: You probably can't move the trigger, but depending on how the trigger is mounted in the plate, you could add material to the lock side of the trigger. In most American guns the trigger is located in the center line of the stock. This isn't the case with European guns. As shown with the French fowler above, the trigger is often mounted off-set towards the lock. The trigger will then contact the sear arm closer to the pivot and not way out at the end of the sear arm. This is more efficient and will reduce the pull.   

[Don Getz]

RAT.........your last statement is wrong.   If you move the trigger in or out, away from or closer to the lock, will have NO
effect on the trigger pull.   If your trigger has a hard pull,  the pivot point of the trigger  is too far from the sear.  By
moving the trigger in or out will have no effect on the trigger pull,,,,,,,,Don

[wet willy]

Thanks to all for the advice on lightening the trigger pull. The lock is a small Siler, so extra sear springs and sears appear available if I mess one up. I'll try Getz's advice to move the sear bar closer to the trigger pin, and grind off some of the sear spring to make it lighter. I have a brazing torch that should get the bar hot enough to bend without cracking.

Lesson learned about finishing stock pre-inletted for both lock and barrel: get the barrel where you want it relative to the lock inlet so the breech face is just behind the touch hole, THEN inlet the trigger so the blade hits the sear bar about 1/4" behind the pin, and THEN inlet the trigger guard.

A person I know skilled at shaping stocks from a blank says to inlet the barrel first so the tang blends nicely with the grip, then inlet the lock so the pan is correctly placed relative to the breech face, the inlet the trigger.

[snowdragon]

Something I do quite a lot to lighten the trigger pull is to curve the trigger blade. On most locks, the sear bar actually moves rearward just a hair, as it travels up. The angle of the trigger blade tries to push the sear bar forward and up, which causes a conflict in direction, and results in a heavy trigger pull. If you file a downward curve on the top of the trigger blade, starting at the point where it first contacts the sear bar, it will create a sort of cam action, and the sear will initially start moving back and up. Doing this will increase trigger travel, but only slightly. Works for single or double triggers. 

If you try this fix, just file a little at a time, then try it. If you file too much of a sharp curve, you could end up with a long trigger travel.  Once you are satisfied with the feel, polish the contact points on both the blade and the bar.

Not the end-all fix, but may be just enough to make your problem acceptable.  And you're right, the trigger blade should contact the sear bar close to the pivot point. I never go past center of the trigger blade. Good luck. Bill

[Jim Kibler]

RAT.........your last statement is wrong.   If you move the trigger in or out, away from or closer to the lock, will have NO
effect on the trigger pull.   If your trigger has a hard pull,  the pivot point of the trigger  is too far from the sear.  By
moving the trigger in or out will have no effect on the trigger pull,,,,,,,,Don

The closer the trigger is to the lock plate, the better the design is from a mechanical standpoint.  This will probably decrease the trigger pull to some degree, but my gut feel is that it would not be that significant.  The point is that when you are pushing on the sear out away from the plate or pivot point, you put a torque on the sear pivot, in a direction perpendicular to the rotation direction.  Not ideal from a mechanical standpoint.  In reality, probably not that big of a deal.

[Don Getz]

Jim......you are correct, but the difference would be extremely light.   If we are talking about a "Chambers" siler lock,
which has good fits on the hole thru the sear, it would be extremely difficult to tell the difference.  When installing a single trigger, pinned high thru the wood, I have found that pinning the trigger just under 1/2" seems to work fine.  I also do
some stoning on the sear and sear notch on the tumbler.........Don