Still can today.
A black powder, muzzle loading cannon is unregulated.
Breach loading cannons and those using smokeless powder are regulated as Destructive Devices, and anyone who can pass a background check and lives in a state that doesn't ban DDs can buy one, have one built or build one themselves.
Still can today. A black powder, muzzle loading cannon is unregulated. Breach loading cannons and those using smokeless powder are regulated as Destructive Devices, and anyone who can pass a background check and lives in a state that doesn't ban DDs can buy one, have one built or build one themselves.