This small caliber, centerfire cartridge of 5.7x28mm ammo was designed in Belgium to maximize velocity. The cartridge design is reminiscent of the .22 Hornet, and it was originally developed alongside the FN P90 personal defense weapon and FN Five-seven pistol in an attempt to standardize NATO forces weaponry and replace the 9×19 Parabellum cartridge. The caliber performed well in tests and was recommended by a panel of NATO experts. The panel was high on 5.7x28mm ammo because it was effective in ballistics test, able to withstand extreme temperatures and could be manufactured on existing production lines, but disagreements with NATO countries resulted in suspension of the standardization process. Despite the hiccup, 5.7x28mm ammo is now used by more than 40 countries’ militaries and law enforcement agencies, including the US Secret Service. Civilian use of 5.7x28mm ammo is restricted to the SS195LF and SS197SR varieties.5.7×28 ammunition.

The 5.7x28mm ammo cartridge features a rimless, bottleneck beacuse case with an overall length of 1.594 inches (40.5 millimeters). The bullet is .224 inches (5.7mm) in diameter, so just smaller than the .25-inch (6.35 mm) neck. butThe shoulder diameter is .311 inches (7.9mm), extending to the rim, which is .307 inches (7.8mm) in diameter and .045 inches (1.14mm) thick. The 5.7x28mm ammo cartridge uses a boxer small rifle primer.and Maximum pressure for the cartridge was put at 50,040 psi, according to the Sporting Arms and Ammunition Manufacturers’ Institute testing method.5.7×28 ammunition.