Percussion lock mainspring question

[Larry (Omaha)]

Have a little percussion rifle I put it together in the 70's. I never shot it much, but lately, decided to improve some of the flaws it had. At this time I will only discuss one. The cocking effort was waaaaaay too stout. I thinned the mainspring in two areas. The main leg that connects to the tumbler, (thickness) and the whole spring width ways. It came out to my satisfaction, but I wondered where it really should be according to any stats out there.
It is around 10 lbs now.
Flintlocklar

 

[plmeek]

I don't know if you can reduce it to a single number. The mainspring needs to be strong enough to consistently pop a cap and resist the blow back force so that it doesn't move the hammer back to half cock. Some may like it strong enough to hold the hammer and cap on the nipple to minimize hot gases and particles hitting your face. The nipple can influence things since a worn and enlarged nipple will allow more hot gases to blow back.

 

[LawrenceA]

I am sure people with more experience will pipe up but in my humble experience..
A percussion lock is not as dependant as a flintlock on spring power as all it needs to do is possibly push the cap down, a little, and crush the priming compound.
It does not need to scrape steel shavings or the like.
Based on this the affects of weakening a percussion Mainspring would be:

• less stress/wear on lock components;
• less stress on lock mortice;
• as you mentioned easier to cock;
• slower lock time (wouldn't notice);
• less reliable if using bad fitting caps;
• As plmeek said about gasses;
• less chance of nipple damage.

So really, as long as the lock is still reliable then no real problem.

 

[Phil Coffins]

That’s an interesting question, I measured a couple in my parts drawer and one for a revolver is 120 grains and a V spring for an unknown lock is 250 grains. But then I tried using a scale on a double barrel ml shotgun and to full cock got 9.5 lbs and 15 lbs . But I agree with others there’s a lot more involved then just weight of pull.

 

[LawrenceA]

That’s an interesting question, I measured a couple in my parts drawer and one for a revolver is 120 grains and a V spring for an unknown lock is 250 grains. But then I tried using a scale on a double barrel ml shotgun and to full cock got 9.5 lbs and 15 lbs . But I agree with others there’s a lot more involved then just weight of pull.

You are right.
Thinking about t I have a couple of doubles and the hammers vary considerably between barrels.

 

[Larry (Omaha)]

I don't know if you can reduce it to a single number. The mainspring needs to be strong enough to consistently pop a cap and resist the blow back force so that it doesn't move the hammer back to half cock. Some may like it strong enough to hold the hammer and cap on the nipple to minimize hot gases and particles hitting your face. The nipple can influence things since a worn and enlarged nipple will allow more hot gases to blow back.

Not looking for a single number, just ballpark as I know every gun is different. Blow back is an issue that I never considered , but I shoot my flinters 98% of the time anyway. This is a short little half stock 45, and I don't think that will be an issue. If it is, I can V out the front of the hammer nipple cavity. ( no idea what that is called)
Thanks for the reply
Flintlocklar