And a BPCR is a Cartridge rifle not a muzzle loader. A different animal all together.
Not quite true, as Harry Pope and Dr. Franklin Mann and many other fine Schuetzen shooters of the late 1800s loaded their breech-loading rifles with a plugged case in the chamber and then used a false muzzle to push the bullet down the bore to be just above the case.
Some records at 200-yards, set over 100-years ago, remain unbeaten. The purpose was to pre-engrave the slug into the rifling, but eliminate any fins or flash (from the bullet base) that could occur as a bullet is pushed into the bore.
I do agree in principle that they are not true muzzleloaders.