[ Hunting ] Open Question : I live in Florida , Does anyone know were in Florida or online I can buy Ammo for a 12 Gauge Shotgun from 1912?

it is a working 12 Gauge Shotgun from 1912, since 1912 the 12 Gauge ammo has changed, if I were to fire modern day 12 gauge shell in my 1912 12 gauge the barrel would expload