The 5.7x28 mm rounds are bottlenecked cartridges with 5.7 mm (.224 inch) bullets and come in several versions. The 5.7x28 mm cartridges have high muzzle velocity and low recoil, and were designed to be more effective against modern body armor when used in pistols, submachine guns, or carbines.
Some military and police personnel view the 5.7x28 mm SS190 skeptically, although it is touted as a solution to defeating modern body armor. Many regard the SS190 as having insufficient "stopping power" for law enforcement use and this topic has seen much debate. A brief controversy ensued in the United States in 2004 when it was claimed by the Brady Campaign that the civilian-legal SS192 cartridges are able to pierce Level IIA body armor when fired from the Five-seveNpistol. All civilian-legal game hunting cartridges, and even several pistol cartridges, are capable of such penetration. The ability of SS192 to pierce body armor as claimed by the Brady Campaign was not confirmed with facts or data by any authoritative agencies or sources. The ammunition was not restricted for civilian sales, since it is not legally recognized as armor piercing by the BATFE. Nonetheless, FN chose to withdraw the SS192 from the market and replace it with the SS196SR. The SS196SR's performance against armor is diminished due to a heavier varmint bullet (leading to lower muzzle velocity) and a polycarbonate tip that promotes expansion and fragmentation upon impact.
FN's 5.7x28 mm brass cases are covered with a special polymer coating for easier extraction on the Five-seveN pistol and PS90 carbine due to the high chamber pressures and lack of case tapering. In addition, the coating insures proper feeding and function in the P90 magazines.
An early prototype round. It used a lightweight 1.5 g (23-grain) full metal jacket bullet with a polymer core. It was abandoned in 1994 in favor of the heavier SS190 projectile, which has greater potential for accuracy and penetration, as well as being shorter and thus easier to fit in FN's then-upcoming Five-seven pistol.
The SS190 AP ball FMJ is designated as armor piercing (AP) ammunition, designed to penetrate body armor. Its sale to civilians is restricted. The SS190 bullet has a steel penetrator and an aluminium core. It is interesting to note that the SS109 FMJ bullet is essentially of the same design, except it uses a lead core with a steel penetrator. The SS109 is frequently found in civilian-legal M855 loads sold as surplus or contract-overrun ammunition.
FN Herstal has stated that the SS190 round will easily penetrate protections that stop normal pistol rounds, but will not penetrate protections that stop the 5.56x45 mm NATO round such as Level III armor. The SS190 has demonstrated varying penetration depths of about 250 mm to 330 mm (10 to 13 inches) in gelatin testing by various agencies. The Royal Canadian Mounted Police Academy forensics laboratory tested SS190 fired out of a P90 into 10% ordnance gelatin, 10% gelatin covered with heavy clothing, and 10% gelatin covered with Level II soft armor. The average penetration depth in all test events was approximately 264 mm (10.4 inches); the temporal wound cavity did not exceed 91 mm (3.75 inches). Testing of the P90 done by Dr. Gary K. Roberts DDS showed an average of 300 mm (12 inches) penetration in 10% ballistic gelatin. Houston, TX SWAT has also done testing with similar results. Many have asserted that these figures are not deep enough, as the current FBI minimum penetration depth is 300 mm (12 inches) in 10% ballistic gelatin.
Combustible chemicals packed in the rear of the projectile create a contrail visible up to 200 meters. The L191's ballistics are almost identical to those of the SS190. L191 tracer ammunition has a red tip. Its sale to civilians is restricted by FN.
Features a hollow point bullet. SS192 ammunition uses a 1.8 g (28 grains) unmarked hollow tip, with an aluminum core. SS192 can be differentiated from SS195LF (lead-free; see below) by the brass-colored primer. Production of this round has been discontinued, and it has been replaced by SS195LF.
The SB193 cartridge features a 3.6 g (55 grain) Sierra Game King FMJBT (Full Metal Jacket Boat Tail) projectile. The SB193's low muzzle velocity eliminates the distinctive "crack" created by supersonic rounds when used in conjunction with the P90 Gemtech sound suppressor. The SB193 suffers from greatly reduced penetration and range, but benefits from slightly lower recoil. The white colored bullet tip can identify SB193 subsonic ammunition. Its sale to civilians is restricted by FN.
The T194 training round is an early version of the SS192. Visually, it is the same as the SS192 but has a green tip and silver-colored primer. The bullet weight/velocity of the T194 are identical to the SS192 and the newer SS195. The T194 round was discontinued in 2002.
The SS195LF cartridge features a lead-free primer, and lead-free bullet with similar ballistics to the SS192 round. It features a 5.7 mm (.224 inch) 1.77 g (28 grains) copper jacketed aluminum core bullet. The SS195LF cartridge may be identified by the unmarked, hollow void at the tip and the silver-colored lead-free primer. SS195LF is available to civilians and does not penetrate Level IIIa soft vests. Note: Some PS90 owners may experience intermittent problems with SS195LF lot FNB06C971-016
The discontinued SS196SR cartridge was replaced with SS197SR. Civilians can still purchase remaining lots of SS196SR. The SS196SR cartridge features a 2.6 g (40 grains), 5.7 mm (.224 inch) diameter Hornady V-Max bullet. The polycarbonate tip in the V-Max bullet enhances expansion of the bullet. The red colored tip differentiates the SS196SR from the blue colored tip of SS197SR.
Fiocchi currently manufactures SS197SR under contract for FN Herstal. The SS197SR cartridge uses the same 2.6 g (40 grain) 5.7 mm (.224 inch) Hornady V-Max projectile as the SS196SR, but it is loaded for a slightly higher muzzle velocity. The bullets have a blue-colored polycarbonate tip. The first SS197SR boxes exhibit the modern FN blue and black colored packaging as shown in the photographs. Newer SS197SR boxes have a similar exterior appearance to the SS196SR and SS195LF boxes. These white cardboard boxes have an adhesive label, marked "Made in Italy”, which helps prevent cartridges from falling out of the box during shipment. The colored boxes rely solely on the flaps and do not use an adhesive label. SS197SR is available to civilians.
A new cartridge that is being planned for release. Current information indicates the SS198 will be identical to SS195LF but loaded for a higher muzzle velocity to boost the penetration in soft tissue. It will be restricted by FN Herstal (not by the BATFE) for sale/distribution to law enforcement and military customers as a duty cartridge.
Note: Due to the longer 40.74 cm (16.04 inches) barrel of the PS90, the muzzle velocity of SS195LF is 75 m/s (250 ft/s) faster, while the muzzle velocities of SS196SR and SS197SR are 45 m/s (150 ft/s) faster.