Trigger lightening.

[beleg2]

Hi,
This is not strictly on rifle making but on lock repairing.
My Kodiak double rifle, trigger pull is heavy on both triggers but I have problems with front trigger (right barrel).
It looks like the main spring is too heavy, actually it is thicker and it does not bend correctly.
What about lightening it by filing a bevel on the outside corner?
Any advice would help.



Thanks
Martin

[P.W.Berkuta]

Hello beleg2, from what I see I don't think your main spring is too stiff (only a guess by the thickness of the legs). What I do see is that the sear is at a high attack angle to the tumbler. I don't think you can reduce the pull weight much with that sear. If it was me I make a new sear with a higher pivot point to nose angle or stoning of the sear nose angle might help a little but be carefull! I bet you got a trigger pull weight of around 7 to 10 pounds.

[northmn]

The mainspring has little to do with trigger pull.  Check the sear springs and see if they are stiff.  You only need enough tension to place the sear into the notch.   Polishing the sear engagements requires a little experience but will also help  You need to know the geometry which requires maintaining a matching angle to the sear face and the sear.  If the thing does not have a fly in the tumbler to keep it out of falling back into halfcock then you are limited to lighteneing the trigger pull without seeing it go to halfcock.

DP

[beleg2]

Thanks for your answers.
I thought about lightening main spring because I have polish all contacts.
It is much better than it was out of the box, but would like it a little lighter.
Also, I thought that lightening the main spring I can get lower friction between sear and tumbler.
I can not lower sear spring weight as much as I could, nore would be dangerous.

Thanks
Martin

[Long John]

I agree with northmn.  You can lessen the trigger pull by working on the sear spring/sear engagement.  I don't really like the shape of the working arm of the sear springs.  They approach the sear surface at a very steep angle.  But the force vector for the spring is a straight line from the contact point to the bend of the working arm.  By filing the contact point so its end surface is parallel with the bearing surface of tthe sear you can eliminate any drag.  Polish the bearing surfaces of the sears.  Polish the ends of the sear springs.  You can lighten the sear spring pressure by making the sear spring working arm narrower in the direction perpendicular to the spring travel.  Do this a little at a time and make your file strokes parallel with the sear spring working arm. 

Best Regards,

John Cholin

[T*O*F]

I note that there are excessive drag marks on the upper lock where the tumbler is dragging against the plate and bridle.  It could be something as simple as you have overtightened the bridle screw that goes thru the sear, causing it to be clamped.  That screw should be threaded with a positive stop so it bottoms before it squashs the bridle against the sear bar.  Unfortunately, most locks use pre-threaded machine screws that have too many threads.

As for the tumbler/sear relationship, there are 3 conditions which can exist.

||  Left mark is sear tip.  Right mark is notch face.  This is the ideal mating of the two.

|\  This is an unsafe condition as the sear can slip off the notch if jarred.

|/  In this mating, when the trigger is pulled the sear must cam the tumbler forward before it can release.  You can check for this by slowly pulling the trigger while observing the hammer.  If it moves at all, it is the cause of your hard trigger