Whoever told you that nonsense doesn't have your best interest at heart FlaBoy18...No cartridge, center fire, or even breech loaded firearm is legal during the ML season in Florida.
Muzzleloading guns firing single bullets must be at least .40-caliber. Muzzleloading guns firing two or more balls must be 20-gauge or larger.
“The legal types of guns for use during the muzzleloading gun season use black powder or a non-nitro-cellulose substitute and are fired by wheel lock, flintlock or percussion cap ignition (including 209 primers). Muzzleloaders using smokeless powder, those that can be loaded from the breech or those with self-contained cartridge ammunition capabilities are not legal during this period. Shotgun or 209 type primers are considered percussion caps and are legal to use.”