Only fact. ammo made is 60 gr. HP at 2800 fps. I felt this load/bullet too light for deer so I a dumped deer with the biggest 75 gr. HP I could find. Sierra. Figured that the varmit hp would expand at slower .256 velocities. got the deer at 60 yds but bullet went through. Load from hornady #4 manual years ago. 13.5 gr. 2400 powder CCI 400 primer winchester brass. About 2350 fps. Never busted bobcat with it but 60 gr. 25-20 at 2000 fps does it well so figure the .256 will too. Loaded up some 85 gr. blue tipped nosler ballistic tips bot not fired them yet. Started with 12 grs. H-4227 for about 2000 fps according to manual. Hopes this helps. Have fun and bangaway.