45 or 50 cal?
 

I'm going to get my first ML soon, within the next week or so. My question is, should I get the 50cal or the 45cal?

My thought is there probably isn't that much difference. On paper, I would think the 45 would have a little higher muzzle velocity and a little "less" knockdown.

Am I close?

I'm looking at aCVAPro 209 Magnum Rifle with Scope - Nickel/Black Fleck from Cabelas for $330. Both the 45 & 50 cal seem to be the same price.