There are many types of firearm ignition. Rimfire and centerfire are just two types f fixed ammo ignition. No matter what typr of firearm, there are three basic places to load, the breech, the muzzle and in the middle and even a combination of these. Of the types of ignition, there is matchlock, wheel loock, flint lock, tape primer, percussion, needle fire, rim fire, centerfire and electric. Even during flint lock days, there were breech loaders. Ferguson, a famous Scot marksman, invented a flintlock, breech loading rifle that was manufactured and imported to the colonies for use by the British troops in the 1770's. There were percussion breech loaders, like the Jenks monkeytail, the Sharps percussion breechloader, Maynard, and others. Though they used black powder and a flint, or percussion ignition system, they were breech loaders. In the 1830's the first bolt action rifle was patented. It fired a caseless cartridge, which was ignited by a needle being thrust forward into the base of the cartridge, the roughened surface of the needle would strike match material causing ignition. It is another type of breech loader that was not rim fire or centerfire, but was the direct ancestor of the bolt action rifle. The 1840's Volcanic Arms lever actions were needle fire ignition guns, and they made lever action pistols as well as rifles. A muzzleloader is simply a gun that loads from the muzzle. Some of the most accurate guns eer made, were centerfire ignition guns that were made to have the cartridge full of powder inserted in the breech and the bullet loaded from the muzzle. (Google the gunsmith Harry Pope, who made many of them) Then there are those odd guns that do not load from the breech or the muzzle. These include such firearms as the cap and ball revolver or the swivel breech Greene and Hall rifles. The entire breech of the gun swiveled upward and the powder and ball would be loaded from the front of the chamber and then swiveled back down in line with the barrel. So when the Pa legislature & Pa Game Commission wrote the regs they included rim fire and centerfire, which are two types of igntion generally used in breech loaders and all muzzleloaders, referring to the guns that load from the front, regardless of ignition. The list does not include all types of firearms ignition nor all types of places to load guns. A Ferguson flint lock breech loading rifle, while historically correct for the revolutionary war, is not a muzzleloader and not rim fire or centerfire, and therefore is not legal for hunting in Pa. for deer or small game. Same for the breech loading percussion rifles such as the early Sharps and Maynards. So you question assumes that all firearms fall into one of the three categories, of muzzleloader, rim fire or centerfire, but there are dozens od designs of firearms that are not included in those three. The cap and ball revolver is probably the most commonly encountered firearm that does not fall into one of those three categories.
Now I fault the Game Commission for the way the regulations are written. Certainly a Sharps Breech loading percussion rifle of 54 caliber and capable of using 80 grains of powder is more powerful than many centerfire cartridges that are legal for deer, but yet, the gun may not be legally used for deer in Pa. Nor for small game. A Ferguson flint lock breech loader is also equally powerful, but not legal for deer in Pa. Not just muzzleloader season, but all seasons. It isn't legal for large or small game under the Pa regs.
So if I call the commission and get some busy distracted person and ask, can I use my ferguson flint lock during the early muzzleloader season, the person at the commission is likely to hear flint lock and assume it is a muzzleloader and will 98% of the time say (incorrectly) yes. If were to ask if my Ferguson Flint lock BREECH LOADING rifle is legal for deer in PA, the commssion emplyee will most likely say (correctly) NO. Alot of people mistakenly classify all black powder arms as Muzzleloaders, but that is not the case. There were all kinds of firearms that used black powder but were not muzzleloaders.
