Good Morning Mr. Morrow, and welcome to the forum!
I have owned and operated five India origin smooth bores, and still own four, (all from Loyalist Arms Canada), plus I've worked on about a dozen others, some LA and some MVTC.
So I don't like to "mess about" much with frizzen or main springs. They can be "twitchy" when you do this and you go from a small problem to a non-working or broken spring, which is a pain in the arse since like the originals..., the parts aren't interchangeable. (Yay for authenticity :shocked2:
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Luckily, the problem you report is not unknown, whether it's an India origin musket, or other guns or rifles.
First, sometimes the geometry of the flint to the frizzen is the problem NOT the spring. You have to take a good look at the edge of the flint and how it's striking the frizzen face. If it's very close to 90 degrees, it's the geometry.
So to correct this without trying to bend the cock..., you wrap the flint in a thin sheet of lead (pound a musket ball very thin with a hammer on concrete, and cut a slot for the jaw-screw to touch the rear of the flint). Trim off the excess lead after you install the flint. Take the excess, trimmed off lead, and cut a small portion about the thickness of a small, wooden match and the width of the lower jaw of the cock. Open the jaw on the cock, and place this extra lead piece just under the back of the flint wrapped in lead. Retighten the jaws. This will raise the back of the flint, and cant the front edge down, giving a better angle. Try the lock and see if this has helped. Remember this "trick" as you can't tell what each flint will do since they are all unique.
IF the angle is good for the flint edge at the frizzen face, and it's still eating the flint...,
You want to take a look at the frizzen "cam"...that's the piece of metal where the frizzen contacts the top of the frizzen spring. That's can be too long, but sometimes it just needs polishing where it meets the spring. The sides of the frizzen where the frizzen screw passes through, which can rub on the lock..., also need to be polished. Finally the top of the spring where the cam moves can also need a polish.
You do this
all by hand for if you take off too much of the actual cam..., you're back in the realm of "pain in the arse" problem. Don't get impatient and use a grinding wheel or other power tool. I like to use 800 grit wet/dry emory paper and a drop or two of oil. Wrap it around a metal file to reinforce it, and polish the sides of the frizzen cam. You can also polish the inside of the bridle, and don't forget to polish the top of the frizzen spring.
Once both sides of the cam are polished, you move to the actual cam. I like to use a fine sharpening stone with a drop of oil, because it is a slow process and because the frizzen is supposed to be pretty hard :wink: . I polish where the cam engages the spring, and this takes time and constant checking on the progress you're making. "Stone" the cam for a few seconds, perhaps keeping a stroke-count, and then examine. Once it's polished check the fit and action, and repeat as needed. You should notice improvement as you go, and as the surfaces get smoother. Once you get the frizzen opening right, and not eating the flints, you switch and give it a finer polish with the paper wrapped around the file, and a drop of oil :wink:
LD