A muzzle loader varies substantially from state to state. Pa really has no such definition. In some states any thing you stuff a bullet down the front of qualifies, even a 30-06 bolt action. Plain English requires that something goes down the front, i.e. loads from the muzzle. Many folks, including the game agency officials, have forgotten that there are flint, percussion and centerfire guns that load from either the breech, the muzzle, or somewhere in between. Here in PA, we can't use a breech loading percussion sharps, a ferguson breech loading flinter, or any Hall or Burnside carbines for any big or small game. Just plain illegal. Only centerfire, rimfire or muzzleloaders are legal for hunting. It is kind of stupid that a person can use any centerfire, no matter how pitifully anemic, like a 32 S&W for deer or bear, but not a more suitable firearm, like the perc. Sharps. Yes we have two muzzleloader seasons, one for any muzzleloader 45 cal and over and a late season for only flintlock muzzleloaders. No wheel locks, no matchlocks.
No flint rifles with half soled frizzens.