1803 Harper's Ferry Zoli Lock Spring Too Strong

[springfield art]

As the headline says, my mint, newly acquired 1803 Zoli Harper's (1973) has a lock mainspring that is way too strong. Any suggestions who could lighten it up? Without shipping the whole gun? Just fishing for ideas at the moment. Thanks.

 

[Mattox Forge]

Duplicate

 

[Mattox Forge]

You could do it.
File the width narrower (see link below for a picture that clarifies "narrower width" 1598308770945.jpeg) until it has the weight you want. Reduction of the width is directly proportional to the reduction in strength by percentage, i.e. 5% width reduction is a 5% force reduction. Remove corse file marks with progressively finer toothed files. Finally polish it.

Here are a few disertations on the topic.
https://www.muzzleloadingforum.com/threads/lightening-a-mainspring.123694/
Mike

 

[64Springer]

Use a belt sander and keep the spring cool with plenty of water.

 

[Flint62Smoothie]

Yes, my Dad would always say … put it in the water more than on the wheel!

Not that we always did, but it sure gets the point across … don’t overheat the metal.

 

[springfield art]

You could do it.
File the width narrower (see link below for a picture that clarifies "narrower width" 1598308770945.jpeg) until it has the weight you want. Reduction of the width is directly proportional to the reduction in strength by percentage, i.e. 5% width reduction is a 5% force reduction. Remove corse file marks with progressively finer toothed files. Finally polish it.

Here are a few disertations on the topic.
https://www.muzzleloadingforum.com/threads/lightening-a-mainspring.123694/
Mike

Thanks for the tip! Didn't realize 'narrowness' affected it; thought you had to 'thin out' the arms. Will check out link!

 

[64Springer]

Yes, my Dad would always say … put it in the water more than on the wheel!

Not that we always did, but it sure gets the point across … don’t overheat the metal.

So true.

When in doubt, drown it.

 

[James Kibler]

How do you know it is too strong?

 

[wiscoaster]

How do you know it is too strong?

Yes, I was wondering the same. You don't really know without comparing against another of same make and model.

 

[gemmer]

Send the lock to Brian at Cabin Creek muzzleloading.

 

[Johnny Tremain]

When I bought a Pedrosorry 1803 the frizzen spring was so strong (330lb) it snapped the frizzen clean off.
I took it and the new frizzen to a ML gunsmith and he ground the spring down by hand.
It worked great until I gave the rifle away.

 

[gemmer]

Send the lock to Brian at Cabin Creek muzzleloading.

I meant Brad. Sorry.