mnprohunter
If this is true then why aren't more people using .45's and not .50? And also why are .50's so much more popular?
Well it is sort of true.... Energy is a function of velocity and remaining velocity at the target.
Example a 40/200 grain bullet fired from a 45 cal @ 23/24/2500 fps second developes a given energy. But it is also know that the lighter bullet will loose energy faster than a heavier bullet fired at a slower velocity... The other thing is that you can shoot that same 40/200 grain bullet from a 50 cal at near the same speeds.
Another factor is the burn rate of the powder that pushes the bullet. In a centerfire you can get powder with lots of different burn rates to drive that 45 cal bullet efficiently. BP and ML subs you do not really have the luxuary of a lot of different speeds. With the lighter 45 cal bullets you may not even burn all the powder before the bullet is out of the barrel.
If it were me and this is my opinion only if I were shooting beyond 175 yards I really would want a 50 cal with a heavier bullet than is available in 45 - unless you are talking a Lead conical. A 45 lead conical can be had that weighs 460 grains from Bull Shop - that will carry the energy but it will not be as fast...
Hope some of this makes sense - somebody better than I will explain further...