Propellant charge BC-E (BMCS)

The propellant charge BC-E (manufacturer's designation XE) is the lower module of the bi-modular charge system BMCS (Bi-Modular Charge System) for 155 mm guns. These are second-generation modular charges for separate-loading ammunition.

The system consists of two types of modules. The lower module BC-E covers short ranges (zones 1 and 2): zone 1 — one module, zone 2 — two modules. The upper module TC-F is intended for long and maximum ranges (zones 3–6, three to six modules). The modules differ in marking, colour, shape and a conspicuous black stripe.

According to its developers, the bi-modular system is easier to handle than fabric bags, and the logistics of storage, transport and use in combat are simpler. For more on how it differs from the classic modular charge system, see the separate article.

The charge was developed primarily for 155 mm guns with a 52-caliber barrel and a 23 L chamber. Tests have shown that the system can also be used in guns with barrel lengths of 39, 45 and 47 calibers and chambers of 18–25 L. The developers caution that the geometry of the modules may have to be adjusted for a particular gun. According to the manufacturer, the system works in guns with 45- and 52-caliber barrels, while in old 39-caliber guns no more than 5 TC-F modules may be used.

The BC-E case is fully combustible and waterproof. Inside are single-base multi-perforated grained propellant, an ignition set with a protective film (CBI and black powder), a fabric wrapper, an anti-copper additive and a cord.

Advantages of the bi-modular system (per the manufacturer):

• Versatility: complies with JBMoU (Joint Ballistic Memorandum of Understanding), suitable for all types of 155 mm projectiles.
• Operating temperature from −50 to +63 °C.
• Moderate barrel wear.
• Reduced muzzle flash.
• Automatic and manual loading are possible.
• Shelf life of more than 15 years in original undamaged packaging at an average temperature of +25 °C.