Those #'s sound about right. You can harden them somewhat by droping them while hot into water, or by an oven heating and water quenching method. I drop straight from the mold into water for any of my faster stuff. My .475 shoots 1350 fps. (440 gr. bullet, 4 3/4" bbl)., My 45-70 1625 fps. with no leading to speak of. My brothers 45-70 goes 1800 fps., likewise with no leading, all with great accuracy. Wheelweights work very well for me and are cheap. Good shooting to you.