The Initial run of 500 S&W Mag (R) cases was built to use large pistol primer per Smith & Wesson and Cor-Bon specifications.

On July 28, 2003, Smith & Wesson and Cor-Bon changed the specification of the primer pocket to be a large rifle.

Rifle primers are the same diameter as pistols except they are approximately .006" taller. This was done to prevent the primer from being pierced by a firing pin when loaded with max loads and heavy bullets (bullets over 400 grains).

It was determined that a hole in the primer allowed pressure to damage the firing pin and bushing, kind of like a cutting torch and the harder cup of a rifle primer will prevent the occurrence.

Product Code: 4510

For more information visit: https://www.starlinebrass.com/500-sw-mag-brass/