Yep, same bullet for all of them. The 54 cal ML uses a .50 bullet and the .50 cal ML use a 44 or 45 cal bullet.

So basically winchester only makes the two larger platinum bullets, they just use them in different delivery systems is all.

Hornady is the same way. Most of your muzzle loading bullets are just .44 or .45 cal pistol bullets in a sabot. Being over driven in my opinion. That is why I switched to the Precision Rifle bullets. Of course now that I bought a slug gun I may not get to see how they perform on deer. I know they shoot better out of my rifle though.