How about two different commands with two separate cooldowns, one providing the user with a single bullet of pistol and the other command provides a single charge of taser? That way entirety of existing ammo simply adds to new weapon type, if for example each cooldown has 1min period, player could switch from taser to pistol using the first /command and swiftly change back to taser using the second /command while being unable to do so again for a minute to prevent misuse or ammo farming. While this doesn't add two different types of ammo for the same weapon, could it solve the 1 handgun limit issue?