Buffalo Bore Heavy ammunition is loaded to be some of the most powerful and highest quality ammunition available in . Buffalo Bore Premium Heavy ammunitions is considered safe to use in any 450 Marlin chambered rifle that is in normal operating condition. This ammunition is new production, non-corrosive, in boxer primed, reloadable brass cases.Owner of Buffalo Bore Tim Sundles on Buffalo Bore Heavy 450 Marlin Ammunition: We always use factory stock firearms to determine our published velocities, so you get true, actual field velocities with our ammo -- not exaggerated long laboratory test barrel velocities. Item 22C (500gr. FMJ-FN Barnes Buster Penetrator) 1600 fps Marlin 22 inch barrel1558 fps Marlin 18.5 inch barrelYou'll note that these 450 Marlin loads are generating slightly lower velocities than their 45-70 counterparts. This is because the 450 Marlin brass (as made by Hornady) has a heavier web and as such the powder capacity was lessened, so the amount of propellant we can f...