On the books, California's black powder gun laws don't so much refer to the charging powder itself, but to the type of firearm it powers: the muzzle-loading rifle. California muzzleloader laws essentially treat this vintage firearm as a sporting rifle meant for taking down big-game targets. You'll find the legal process of owning a muzzleloader in California somewhat different than that of owning a handgun or other self-defense type of firearm.
In California, a black powder-powered muzzleloader is mostly subject to state-authorized methods for hunting big game.
State Muzzleloader Regulations
In California, people who wish to hunt may possess only in-line, single-barrel muzzleloaders that fire a single round-ball or conical projectile and that feature open or iron sights, often dubbed "peep"sights. These guns are allowed for hunting during general muzzleloader seasons, which typically fall in late November and early December for deer; September through January for elk; and year-round for wild hogs with the appropriate permits. Depending on the type of game in question, projectiles typically must be at least .40 caliber with a weight of 170 to 210 minimum grains. Muzzleloaders may not be used for hunting in the areas defined as the California condor range.
Carrying a Muzzleloader
Under California law, it's illegal to carry a loaded firearm on your person or in your vehicle while in any public place or any other place where it's illegal to discharge a firearm. A muzzleloader is considered legally loaded when it is capped or primed, charged with powder and has a ball or shot in the barrel or cylinder.
More to Know About Muzzleloaders
During muzzleloading hunting seasons in California, shotshell primers and sabots are legal to use, but pelletized powders, scopes and electronic scoping gear are prohibited. In fact, no electronic or battery-powered devices may be attached to the muzzleloader at all.
While black powder and black powder substitutes are perfectly legal, smokeless powder is not. As for owning the actual powder itself, state laws allow citizens to possess 5 pounds or less of black sporting powder. Naturally, this powder must be for legal use and not for resale, and intended for loading arms of .75 caliber or less.
Disabled hunters living in California can skirt the muzzleloader's strict scope rules via the state's Visually Disabled Muzzleloader Scope Permit Application FG539. There's no fee to file this document, and it can be found and downloaded on the California Natural Resources Agency's website.