Chapter 7 Ammunition Loading

CHAPTER 7 AMMUNITION LOADING Aircraft gun ammunition is developed for specific types of aircraft-mounted guns. The M61A1/A2 uses M50/PGU series 20-mm ammunition. The M50/PGU series consists of various types of cartridges developed for specific applications, including test cartridges, dummy cartridges, target practice, target practice tracer, armor piercing incendiary, high-explosive incendiary, and semi-armor piercing, high-explosive incendiary. Blank and dummy rounds are also used for practice and maintenance. The M50/PGU series 20-mm ammunition is loaded into the M61A1/A2 gun through the linkless ammunition loading system (LALS) series. The LALS transports rounds from the transporter to the aircraft system, and simultaneously transports spent cases and cleared rounds from the aircraft system to the transporter. AIRCRAFT GUN AMMUNITION LEARNING OBJECTIVE: Describe the 20-mm M50/PGU aircraft gun ammunition configuration. Identify M50/PGU 20-mm gun cartridges and describe their uses. M50 CONFIGURATION AMMUNITION M50 configuration ammunition (fig. 7-1) for the M61A1/A2 Navy aircraft gun is issued in the form of cartridges (rounds). A complete service cartridge assembly consists of a cartridge case, electric primer, propellant, projectile, and fuze. All service cartridges have matched ballistics and are electrically primed. CLASSIFICATION The M50 configuration ammunition currently issued is classified as follows: 1. Dummy Cartridge M51A1B1, M51A2 (steel), or M254 (plastic) 2. High-Pressure Test Cartridge, M54A1 (HPT) 3. Target Practice Cartridge, M55A2 (TP) 4. High-Explosive Incendiary Cartridge, M56A3 (HEI) 5. Target Practice-Tracer Cartridge, M220 (TP-T) 6. High-Explosive Incendiary-Tracer Cartridge, M242 (HEI-T) CARTRIDGE COMPONENTS, GENERAL DESCRIPTION The cartridge components for M50-configured ammunition as used in a complete round are discussed in the following paragraphs. Cartridge Case The M103 (brass) and the M103B1 (steel) cartridge cases (fig. 7-2) are marked longitudinally. The 7-1 Figure 7-1.—M50 configuration cartridge. Figure 7-2.—M103 (brass) and M103B1 (steel) cartridge cases.