12.7×55mm STs-130

The 12.7×55mm cartridge is used in some Russian firearms such as the VKS bullpup sniper rifle, the ShAK-12 bullpup battle rifle and the RSh-12 revolver. The cartridge can carry a projectile weighing between from 108 grains and 1173 grains and is predominantly used to fire heavy subsonic loads. The high penetration VKS round can penetrate up to 16 mm of steel at 200 m or body armor up to GOST 5 or NIJ III at 100 m. The accuracy of this cartridge when loaded with precision VKS bullets is claimed to be one MOA at 100 m up to the effective range limit of 600 m.

Despite being chambered in the same cartridge, the ShAK-12 (and RSh-12) would not be able to feed or chamber rounds designed for the VKS due to significant length differences in the bullet component of the cartridge and thus requires its own, shorter, loads. The ShAK-12 rounds have less range compared to the VKS with the maximum effective range of the loads reaching in between 100 and 300 m.

Cartridge variants for use in the VKS

 * STs-130 (СЦ-130) - standard
 * STs-130U (СЦ-130У) - for training
 * STs-130PT (СЦ-130ПТ) - increased accuracy (59 gram bullet)
 * STs-130PT2 (СЦ-130ПТ2) - increased accuracy (solid bronze bullet)
 * STs-130VPS (СЦ-130ВПС) - increased penetration (76 gram bullet)

Cartridge variants for use in the ShAK-12 assault rifle

 * Legkaya Pulya (LP) or "Light Bullet" - Light supersonic lead bullet with an aluminum core weighing 7 grams (108 grains).
 * Tyazhelaya Pulya (TP) or "Heavy Bullet" - Heavy subsonic lead bullet weighing 33 grams (509 grains).
 * Dvukhpul'niy (DP) or "Double-Bulleted" - Two bullets loaded inline weighing 17 grams (262 grains) each.
 * Broneboynaya Pulya (BP) or "Armor-Piercing Bullet" - Lead bullet with an armor-piercing component weighing nearly 18 grams (277 grains).