I can sheda little light on the .44 mag part of the question. I load a 240gr. xtp with 24.5gr of lil'gun and get 1425 fps from my 7-1/2" ruger sbh. and 1880 fps. from a 20" 1894 marlin. I do remember doing a test with h110 and 4227 and the velocity increase was more with the slower burning powder.