I have a BLR in 450 Marlin as well as a Marlin in 45/70. The 450 Marlin is the 45/70 loaded to over 40,000 psi. If you want a powerful cartridge and do not hand load, then the 450 is the way to go. If you hand load, then they both can be loaded up or down. 45/70 factory ammo is easier to find and Garrett loads some 45/70 rounds that are about equal to a 450 Marlin. In addition, more guys are buying the 450 Marlin, but the 45/70 is still more popular based on sales. Using factory ammo, the 45/70 is much more kinder and gentler to my shoulder.
