.500 S&W Magnum
Date: Apr 23 2020
The .500 S&W Magnum was a joint effort between COR-BON Ammunition and Smith & Wesson, which propelled either a 400-grain JSP or a 440-grain cast bullet over 1,600 fps. This power level required S&W to develop its new X-Frame revolver. At 74 ounces (8 3/8-inch barrel), the revolver was large and weighed almost as much as many ultra lightweight hunting rifles. Nonetheless, sales were brisk for several years.
Within the first few years there were technical changes to the cartridge, mostly minor; however, early COR-BON and Hornady ammunition featured Large Pistol Magnum primers, with primer pockets sized accordingly. Some ballistic labs began to experience erratic pressure curves, and select maximum loads were occasionally piercing primers. As a result, primer pockets were changed (deepened) to accept large rifle primers. For several years factory loads were available that contained both primers, but eventually all have changed to the Large Rifle primer and cases have been changed accordingly. Incidentally, all Starline cases that are manufactured with the Large Rifle primer pocket will have the standard “.500 S&W MAG” headstamp and “R”.
It is not advised to use Large Rifle primers in cases that feature the Large Pistol primer pockets, as they will not seat below flush, but rather protrude and often drag on the recoil shield, potentially stopping cylinder rotation. A high primer in a heavy recoiling revolver also has the potential to be dangerous.
Since both case types are commonly encountered by handloaders, the accompanying data was developed with both Winchester Large Rifle and Winchester Large Pistol primers (for standard or magnum). With the Large Pistol primers, the majority of loads tested gave higher velocities with the powder on the base of the bullet, as opposed to powder resting on the primer, which is the opposite when compared to most revolver cartridges. In several instances, loads were discovered that were problematic, with hang fires, wide extreme spreads, etc., with those loads being eliminated from the accompanying data. The rifle primers certainly helped to settle wide extreme spreads, but not always. Therefore, it is suggested to use data as listed.
To prevent bullets from jumping crimp under heavy recoil, and to aid with correct powder ignition, a heavy roll crimp is crucial.