I have 5 muzzleloader, but I have been shooting my first Knight; a 1999/2000? model "original" Disc rifle with a 24" barrel. I prefer the stock on that gun because it has a palm swell. I would put the stock on my Elite, but I don't want to modify it, but I digress. I have never tried 54 cal pellets in my Elite or my Encores, but I have in my Ultimate. I don't have any way to accurately measure the pellets, but they definitely NOT 50 cal pellets in the wrong box.