[8D] Check out www.barnesbullets.com/prodtsx.php the triple shocks are now made up through .458 caliber. They offer a 450 gr. and 500 gr. which is rather a hefty load for anything but dangerious game. The Barnes X regular bullets are made from 300 gr. up to 500 gr.. I mean either the .45-70 or .450 Marlin is a limited range round but the increase in B.C. could help lengthen that a little. The B.C. for the Barnes X 300 gr. is .340 as compared to a flat nose bullet like the Hornady 300 gr. with a .197 B.C.. Quite a difference but the tube feed on the Marlin requires a flat point.