....straight from the regs. There are several other requirements in the regs that I didn't copy over. Most notably no optical sights, no 209 primers and the primer must be exposed to the elements.
(b) A muzzleloading firearm used for
deer must fire a single, non-jacketed
lead projectile of nominal 40 caliber or
larger except that buckshot size #1 or
larger, may be used in a smoothbore
of 60 caliber or larger. Lead bullets
with polymer tips are legal.
(c) A muzzleloading firearm used for
all other big game must fire a single,
non-jacketed lead projectile of
nominal 50 caliber or larger, or fire a
single, non-jacketed lead projectile of
at least 170 grains. Lead bullets with
polymer tips are legal.