Be careful, I know that 10 gr of Unique will separate brass in an 1873, and Universal is very similar to Unique. The shell for a 44-40 is MUCH thinner than a 44 Magnum, and will split or separate easily if pushed too far. Check Hogdon's website for loading data. It's not just a matter of the strength of the rifle action as the ability of the cartridge case to contain the pressure as well, and not send a portion of the propellant back toward the shooter.