Over avarage hunting distances (100 yds or less, with rb, maby 75), the .54 will give you more Oomph as the projectile is tens of grains heavier. If you want to get the most distance for the buck, try the .45 for rb shootin. If you want an elk/bear possibility, go with the .54. The advantage to the .50 is that you should be able to get components almost anywhere (ball, precut patches, rod components like bore brushes. The .45 and .54 usually require doing business with an internet or mail-order house for supplies. I shoot two .54's and do business with any number of good internet providers. Hope this helps. P.S. I own a Lyman Trade rifle in flint, and love it. the fit and finish are great, shoots well.