Each Soviet projectile has its unique designation. This designation looks like: AA-XXXBB where: AA means Initial Literal Index (ILI) it defines type of a projectile; XXX means Main Digital Index (MDI), it defines calibre of a projectile; BB means Optional Literal Index (OLI), it shows additional capabilities/features of a projectile. Table 1. Indexes of the Soviet projectiles Index | Russian term | English equivalent | Initial Literal Index (ILI) | F | fugasniy | high explosive | G | betonoboiniy | concrete-piercing | O | oskolochniy | fragmentation | OF | oskolochno-fugasniy | high explosive fragmentation | OH | oskolochno-khimicheskiy | chemical fragmentation | B | broneboiniy | armor-piercing (old)
| BR | broneboiniy | armor-piercing (new)
| BP | broneboiniy prozhigaushiy (WWII term) | shaped-charge or HEAT | BK | broneboiniy kumulyativniy (later term) | shaped-charge or HEAT | Sh | shrapnel' | shrapnel | She | kartech' | canister | Z | zazhigatelniy | incendiary | D | dymovoy | smoke | S | osvetitelniy | illumination | Optional Literal Index (OLI) | P | podkaliberniy | HVAP | SP | sploshnoy | solid | M | modernizirovaniy | modernized | All other OLIs aren't common for all types of projectiles and used to describe features of a certain projectile. Normally, Soviet armor-piersing rounds are APHE, i.e. with some explosive charge to increase penetration power. If there is no explosive charge, such round is always desingnated «solid» SP. Therefore, the BR-350 means 76-mm armor-piercing high explosive round, BR-350SP means 76-mm armor-piercing solid round, OF-350 means high explosive fragmentation round. According to the Soviet nomenclature, each tandem calibre+bore_length has its unique MDI. For example, 350, 353 and 354 are refer to the 76-mm calibre. The table below is my attempt to systematize these figures: Table 2. Indexes of the Soviet projectiles Calibre | The projectile's MDI | The shell's MDI | 20 mm | 111 | 111 | 25 mm | 240 | 240 | 37 mm | 167 | 167 | 45 mm | 240, 241, 242 | 240, 241, 243 | 57 mm | 271 | 271 | 76.2 mm | 350, 354, 355, 361, 363 | 353, 354, 355, 361, 363 | 85 mm | 365, 367 | 365, 367 | 100 mm | 412 | 412 | 106.7 mm | 420, 422 | - | 121.92 mm | 462, 471 | - | 127 mm | 4891 | - | 152.4 mm | 501, 521, 530, 531, 533, 540, 542, 550, 551 | - | 180 mm | 620, 621, 625 | - | 210 mm | 643 | - | 280 mm | 674 | - | 305 mm | 724 | - | To describe a cartridge-loading shell, the «U» letter used before the ILI. It means «unitarniy» (cartridge-loading ammo). For example: UBR-354P refers to the 76-mm cartridge-loading shell with the BR-350P HVAP projectile. The same is for separate loading ammo but the «V» letter using instead: VBR-471. The «V» letter means «vystrel» (charge). |