RE: 54 or 58 caliber
Given your intentions, and the fact thatyou're going to to buy something anyway, I'd buy the .58cal.
GM makes them as drop-in replacements for TC Renegades and the large size Hawken...I have a GM Flint version 1" x 33" x 1:70"...extremely accurate.
The 279grn ball holds more energy at longer distances than any of the smaller calibers...a big plusfor largergame at longer distances.