Rowdy,
A jacketed bullet can be used with b.p. since, way back when, factories did offer some calibers with jacketed bullets using b.p. as the propellant. They did not for the .44-40 as far as I know and I don't think it would be as good as the lead bullet since the velocity would be reduced due to the higher resistance and thus the bullet would not expand much, if at all.
w44wcf