Lock/trigger problem

[smylee grouch]

You of course don't want the bottom of the sear spring to bind against the portion of the sear at the pivot so you need clearance there but the more you move the sear/sear spring contact point to the rear the more force you will need to trip the sear, ad that to poor sear notch geometry in the tumbler you will indeed have a heavy trigger.

[Bob Roller]

As I said in my rant.This lock missed the quality control phase.
It has a real potential but not as now made.

Bob Roller

[Acer Saccharum]

The closer the sear spring tip is to the pivot point of the sear, the less force it will take to operate the sear.

The lower limb of the spring should be longer. You may have to grind/file/stone the top surface or the sear bar for easier sliding for the spring tip. Warning: the spring tip MUST NOT contact the barrel of the sear pivot.

[D. Taylor Sapergia]

AS has nailed it, I believe.  L & R lock fitters, for whatever reason, grind the business end of the sear spring FROM THE BOTTOM and shorten it too much.  On the example here, and on the one I post now, notice that the tip of the sear spring is ground off so that it falls well short of the pivot boss of the sear.  Because of this, it requires a huge amount of force to trip the sear, assuming the sear nose and tumbler full cock notch are correct.  To correct it, on my lock I heated the spring red and straightened it flat.  Then I tapered the lower leaf end and re-bent the material to provide a longer lower leaf.  Pinching the bend and re-arcing the lower leaf also added to the flexibility of the spring, and it now contacts the sear directly behind the pivot boss of the sear.  Whereas as shipped, I had exactly the same problem as you have, now the lock functions perfectly.
As a side note, I did a complete tutorial of this fix and send it to L & R, but got no reply.

[Acer Saccharum]

Thanks for those photos, Taylor. That is IT exactly.

Thinning a spring that lands too far away from the pivot does very little to lighten the pull. A stiff spring, with the tip close to the pivot takes little effort to move the sear.

Leverage. That's the word. Give me a long enough lever, and I can move the earth.

[D. Taylor Sapergia]

Give me a long enough lever, and I can move the earth.

Sure, but the trigger pull would be horrendous.

[Craig Wilcox]

AND - ya gotta find a suitable fulcrum!

[WKevinD]

Just a follow up note:
I received a (softer) replacement sear spring from L&R, polished it and the tumbler notch and installed the spring. It works perfectly. Fires every time.
Thanks for all the input.

Kevin