The 5.7×28mm is a small arms cartridge developed by FN Herstal for the P90 PDW and the Five-seveN semi-automatic pistol.
Design Details
The 5.7mm cartridge is designed like a small rifle cartridge; the casing has a small neck to accommodate the projectile, which is a 31 grain bullet. The projectile design was modified to FMJ in order to be sold on the commercial market.
Overview:
Conventional sidearms usually use the 9×19 mm, .45 ACP and similar cartridges that are effective for stopping a hostile individual in ordinary circumstances. However, if the individual is wearing a light Kevlar vest, these bullets will be stopped without causing lethal damage. FN claims that thanks to the use of their newly designed 5.7 x 28 mm cartridge, the Five-seveN and P90 is capable of piercing the older U.S. Army PASGT vest at 300 meters range, and a U.S. Army PASGT helmet at a range of 240 meters. However, these penetration statistics are for the military SS190 cartridge. Other available cartridge variants are not armor-piercing, according to the BATFE. These cartridges are loaded with heavier, expanding projectiles driven at lower velocities.
After penetration, the 5.7mm round is marketed as being able to effectively incapacitate an enemy, but there has been controversy over these claims. Conventional hollow point bullets rely on expansion to create a large wound channel, but the Five-seveN's ammunition is designed to hit the enemy, travel a few inches, then tumble end over end and continue traveling in this manner without deforming. This means that the wound it creates would be as tall as the length of the projectile (more than 21 mm), supposedly creating a more grievous wound channel, but without the expansion of a hollow point or the fragmentation of a frangible bullet. As a result, FN claims the round—and the Five-seveN and P90-are suitable for military use.
Feed Systems
This cartridge is fed through detachable box magazines.
Variations
- SS90 Type I - Original version of the round, which features a 23-grain polymer-cored projectile that measures 23.26mm in length.
- SS90 Type II - Redesign of the SS90 with an aluminum frontal core section and polymer rear, projectile measured 24.10mm in length.
- SS190 - Replacing the SS90 in 1993, the SS190 uses a shorter but heavier metal-cored 31-grain projectile, allowing it to be used in pistols such as the FN Five-seveN. A version of the P90 PDW that fires this round was introduced alongside it.
- L191 - Tracer round.
- SB193 - Subsonic round. Formerly designated as SS193.
- SS192 - Civilian-use hollow point round introduced alongside the IOM version of the Five-seveN pistol. It was discontinued the same year that it was introduced.
- SS195LF - Civilian-use hollow point round with a lead-free primer.
- SS196SR - Civilian-use sporting round using the Hornady V-Max projectile.
- T194 - Training round.
- SS197SR - Civilian-use sporting round using the Hornady V-Max projectile. Manufactured by Fiocchi under contract for FN Herstal, and has a muzzle velocity that is 30 m/s higher.
- SS198LF - Uses the same lead-free projectile and primer as the SS195LF, but propels it at a roughly 30 m/s (100 ft/s) higher muzzle velocity. It has a green painted tip, and its sale is currently restricted by FN Herstal to military and law enforcement customers.
Developmental Variations
- 5.7×28.8mm
- 5.7×25mm
Gallery
