9×39mm

History and design

It is based on the Russian 7.62×39 mm round, but with an expanded neck to accommodate a 9 mm (.356 caliber) bullet. The cartridge was designed by N. Zabelin, L. Dvoryaninova and Y. Frolov of the TsNIITochMash in the 1980s. The intent was to create a subsonic cartridge for suppressed firearms for special forces units that had more power, range and penetration than handgun cartridges. The 5.45×39 mm cartridge introduced in 1974 for the AK-74 lacks sufficient bullet weight (at 53 gr to 80 gr) for acceptable energy at subsonic velocities. The bullet of the 9×39 mm is approximately 16 g (250 gr), double that of the normal 123 gr 7.62×39 mm round, and is subsonic. This slow velocity does not produce a sonic boom, but does limit the muzzle energy and effective range of a weapon when compared to non-suppressed assault rifles. The round has an effective lethal range of 300 to 400 meters and a maximum penetration of up to 8 mm of steel. Like the 5.45×39mm cartridge, 9×39mm SP-5 features an airpocket in the tip, which improves its capability to yaw after impact, and thus its effect in soft tissue.

Since the bullet weighs about twice as much as that of the 9×19mm Parabellum, its muzzle energy is about twice as high as that of a subsonic 9×19mm Parabellum bullet, e.g. when fired from a HK MP5SD.

Variants

SP-5 (7N8) - The SP-5 (СП-5) (SP: Spetsialnyj Patron; "Special Cartridge") was developed by Nikolai Zabelin. It is a conventional lead core FMJ bullet, but developed for accuracy.

SP-5UZ - The SP-5UZ (СП5-УЗ) is an SP-5 variant with an increased charge intended for a factory-specific strength testing of the weapons.

SP-6 (7N9) - The SP-6 (СП-6) was developed by Yuri Frolov. It has a hardened metal armor-piercing core. It can penetrate 2 mm (0.079 in) of steel at 500 meters or 6 mm (0.24 in) of steel, 2.8 mm (0.11 in) of titanium or 30 layers of Kevlar at 200 meters. At 100 meters it penetrates 8 mm (0.31 in) of steel, while retaining enough power to neutralize a soft target behind it.

SP-6UCh - The SP-6Uch (СП-6Уч) is an SP-6 variant intended for training.

PAB-9 (7N12) - The SP-6's bullet is expensive, so an attempt was made to make a lower-cost version of the cartridge. The PAB-9 (ПАБ-9) used a stamped rather than machined steel core. It sacrificed too much performance to be usable. As of 2011, its usage is prohibited.

SPP - The SPP (СПП) (SPP: Snaiperskie Povishennaya Probivaemost; "Sniper - Increased Penetration") is a sniper round with an increased penetration.

BP - The BP (БП) (BP: Broneboin'ie Pulya; "Armor-Piercing Bullet") is an armor-piercing round.

Weapons