Buffalo Bore loads their ammunition up to maximum SAAMI specifications, which delivers devastating performance on a wide range of game. Please note that this ammunition is not intended for older guns. It is made for modern firearms only, as some of the ammunition could damage older and weaker firearms. This ammunition is new production, non-corrosive, in boxer primed, reloadable brass cases. Buffalo Bore 458 SOCOM ammunition is designed to be used against all large North American Game like Bison, AK/Yukon moose and very large bears. Because of the big bullet diameter and non-expanding bullet, this load is appropriate for 2,000 lb.+ game animals. It utilizes the many decades old Speer 400gr. JFN bullet. This is an old technology bullet that fills a few roles so perfectly, that it would be a shame to ever update, discontinue or change it. At impact speeds around 1800 fps on large mammals, this bullet will over mushroom and usually come apart, but the 458 SOCOM cannot launch a 400gr. bullet anywhere close to this speed. At impact speeds of around 1600 fps, this bullet mushrooms to about one inch in diameter holds together and penetrates deeply (At least 24 inches).  At impact speeds around 1500 fps, it mushrooms nicely (roughly .85 caliber) and will penetrate about 30 inches. As impact speeds get slower, it mushrooms less and penetrates more deeply until it stops mushrooming at impact speeds around 1,000 fps. Of course, the size of mushroom and depth of penetration will vary depending on which bones and other body parts are struck.