Main spring too heavy!

[major]

I just got back for a local reenactment where I fired 405 blanks over the weekend out of my Armisport 44-40 Spencer.  About the only real problem I had was that I raised a blister on my right thumb from cocking the hammer.  Does anyone know of a good way to lighten the main spring so it is easer to cock but will still have enough force to work the firing pin?
Terry

[Harve Curry]

First order a new spring, so you have a replacement if you mess up.
I've used a bench grinder with a fine stone and grind with the length of the spring, all the while keeping the spring cool with water. Grind the thick part first, keep a uniform thickness and taper. Smooth it out with emory cloth, sanding again the length of the spring. No lines across the spring, that will give a line for the spring to crack on. Don't let the spring get hot, keep dipping in water.
Take a pre-determined small amount off then reassemble and test it.
Hope tis helps.

[major]

Harve
Do you take the metal from the thickness of the spring or narrow the width of it?
Terry

[Fox Creek Kid]

First order a new spring, so you have a replacement if you mess up.

Sound advice as I knew a certain fella................ ......who messed up a mainspring trying to lighten it. 

[Two Flints]

Hi Fox Creek,

Any more info on that fellow who messed up his mainspring?    Do you by any chance know what he did wrong so the Major won't do the same thing? 

Two Flints

[Harve Curry]

Sorry for the delay, I wasn't home.
I have only removed material from the wide flat side. You can remove some from the narrow edge, still keep the filing lines going with the length, I've seen that done.
With the spring in the lock look at where it bends when you cock it.This can give you an idea where to work on the spring.
A Dremel tool is a good help for this to.

[major]

Harve
Thanks for the info. I will give it a try.
Terry