The 50 caliber inline has the capacity to shoot any sabot that's pushed down the 45 caliber muzzle. That includes the .357 and 40 caliber bullets... simply by changing plastic sabots.

Plus - if you look at store shelves, most everything caters to 50 caliber -- so the selection is much better.

Lastly, it's been proven over& over again that 45-cals are more finicky shooters -- meaning my 50-cal Omega likes to shoot almost anything -- but if you throw a 45-cal barrel on it, those bullet choices diminish greatly.

If the price of the 45 is 50% less than the 50 - plus you only plan on shooting it at 100 yards or less, then maybe the 45 cal is a good choice.

But if you don't want to limit yourself, then the 50-cal is a no-brainer.