fuzz, Browning BPCRs were made in .45-70, .40-65, and a very few in .45-90 (called a Creedmore). The largest quantities were in .45-70 caliber but .40-65 are a little easier on the shoulder. Keep checking this and other BPCR forums and the firearm auction sites. Every once in a while you'll find one for sale, but price is slowly going up.
Wayne