Often, the best caliber to choose depends on what use you'll be putting it to and/or how you'll be using it.
For example, if you are going to hunt deer in a dense woods, a short barreled .45, .50 or even a .54 caliber rifle might be best.
You might be surprised by my recommending a .54 caliber, but in a very dense woods, you want to "anchor" any deer you hit since if the deer runs very far, it may be lost or very difficult to find and a short-barreled .54 caliber Hawken is just the "ticket" for that kind of hunting.
If deer hunting in a fairly open woods, I'd recommend either a .45 caliber or a .50 caliber Hawken Rifle with the preference going to the .50 caliber shooting a somewhat heavier round ball for better penetration and killing power.
The .45 caliber would have less recoil than the .50 caliber and be almost as effective on deer.
If you're only shooting paper targets, the .45 caliber is slightly less costly to shoot (less powder and a slightly less expensive round ball)... and the .40 caliber is even less costly as are the .36 caliber and .32 caliber.
There's the "line-up"... take your pick... :v
Strength & Honor...
Ron T.