IMHO what you are seeing is Knights marketing department trying to convince everyone they need to buy another muzzleloader. 50cal is the standard that meets most peoples needs. Suddenly everybody is talking about the 45cal and how flat they shoot. Now it's the 52 because it shoots bigger bullets and it's just what you need for really big or dangerous game. Before if the 50 wasn't big enough people just bought a 54. Only problem was if you shot sabots, the 54 used the same bullet as the 50. The sabot just had thicker petals. These thick sabots sometimes were harder to load. Knight now comes out with this 52. It uses a thin walled sabot and instead of .451bullets it uses bullets for rifles like the 475H&H. I would suggest you go with the standard 50cal. It does a good job and there is an infinate selection of bullets for them.