I know that my mod was far from perfect to begin with, (huge understatement, I know) specially considering how I still don't know the best way to work with the current damage system. If I may be so bold, I do have some suggestions:
-Originally I was going to have the musket-making reaction use more bars, logs and mechanisms, but produce more weapons to account for the use of flint. I think it was making around 4 of them at once.
-A better work-around would be to create an item (perhaps a tool?) to replace the boulder of flint in the weapon-making reaction, which then can be made in large quantities from a single boulder of flint. Like the gunstones are made, perhaps?
Also if I may, while SHOOT_FORCE does affect damage (as far as I know), SHOOT_MAXVEL affects the actual speed of the projectile, however due to how reloading works (again, I'm not 100% sure of this) anyone firing the weapon cannot start reloading until their projectile hits something, so it does affect reload speed a bit, but for the most part that's really dependant on your dwarf's marksman/misc.weapon skill or even their agility level.