RE: 45 caliber VS. 50 caliber
IMO if you are hunting thin skinned animals like deer, and your shots are extreme distance, and we're talking.. 150+ yards, there might be some advantage to the .45 caliber. They claim with the modern sabot round they are flatter shooting.
But here's my point. If your shooting the same weight bullet as the .45, it might have an advantage. But lets say you are shooting a heavier bullet because of the larger caliber and selection. You have a scope on your .50 because you expect longer distances, you have practiced, and you can hit your targets even with more of a rainbow trajectory. At impact you can push a larger bullet that carries more energy.. So where is the advantage?
The one place I see a .45 maybe topping the larger calibers is in a White Conical shooting rifle. Both my .451 & .504 shoot a 460 grain bullet. The .451 being longer, and shorter diameter, and more aerodynamic. Both can be pushed to the same powder charges. Here, the .45 might have a real advantage over the larger caliber. It should be flatter shooting, but hit as hard. And the difference in the size of the hole.. well who will notice when the deer is on the ground.