WV_Hillbilly,
Do you have an energy rating with those .45 & .54 loads? ::
Yes sir, I sure do...
The .45 caliber 230gr Maxi at 1532 fps has 1199 ft.lbs.
The .54 caliber 220gr round ball at 1250 fps has 763 ft.lbs.
And of course the B.C. of that .45 caliber Maxi is probably about 2 1/2 times better than the .54 caliber round ball.
The .54 round ball B.C. is about .05 and the .45 Maxi B.C. is about 1.3
The notion is that if you're strictly using round ball, and you want more energy or "knockdown" power, you have to increase the bore size (which means a bigger, heavier round ball).
The smaller bore caliber can make up for it's diameter by using a conical which increases the bullet weight and the B.C., so you could possibly end up with a flatter trajectory, more velocity, more penetration, and more energy. That's a lot of factors to consider.
No matter what round ball gun or caliber, the round ball has some inherent ballistic characteristics and limitations that you just have to deal with.
Generally speaking, if a round ball starts out at the muzzle at 2000 fps, by the time it's at 100yds, it has lost about half of it's velocity (down to 1000 fps) and down to 1/4 of it's energy (as compared to the muzzle energy figure).
Doesn't matter what caliber round ball it is, though the larger diameter round balls do have slightly better B.C.s, it's not enough to cheer about. Conicals will always retain their velocity and energy figures better than round balls.
BUT... and this is IMPORTANT... a round ball may be MUCH more accurate than a conical in a particular gun, due to type of rifling, twist rate, etc... SO REMEMBER, extra energy won't help you if the bullet misses the target.
Shoot Safely!
WV_Hillbilly