Charge Increment

155mm Charge M203

Type Classification:

M4A2: Std AMCTC 4633 dtd 1966. M4A1: Std AMCTC 4633 dtd 1966.

Use:

This white bag propelling charge is used in 155mm howitzers for firing in Zones 3,4,5,6, and 7.

Description:

The total charge (M4A2 Prop. Charge) consists of 13 pounds of propellant and is divided between a base charge and four unequal increments loaded in white cloth bags. The increments are connected by four cloth tapes sewn to the base and tied on top of Increment 7. The igniter for Charge M4A2 is 3.5 ounces of clean burning igniter (CBI) in a red cloth pad sewn to the bottom of the base charge. A flash reducer pad containing one ounce of potassium nitrate or potassium sulphate is assembled at the front end of the base increment (Increment 3). The seams in the base pad are inverted so that the edges of the cloth are inward to reduce residue after firing.

Functioning:

When the weapon is fired, the primer ignites the igniter charge, and the igniter charge ignites the propelling charge. The burning propellant generates rapidly expanding gases to propel the projectile through the barrel and to the velocity required to reach the target. The flash reducer pads serve to limit breech flareback as well as muzzle flash and blast overpressure.

Difference Between Models,

Shipping and Storage Data:

Model M4A1 is similar to Model M4A2 except that the igniter charge is 3.0 ounces of black powder instead of CBI, the base charge seams are not inverted, and the charge does not include a flash reducer. Flash Reducer M2 may be used with Charge M4A1 when required, but is a separate item of issue.

Tabulated Data:

Complete round:

Type --------------------------------- Separate loading, white bag

Length ------------------------------- 21.0 in, max

Color ------------------------------- White w/black markings

M45, M126, M126A1, M185, M199 Propellant M1 ---------------------- (13.4 lb explosive)

Temperature Limits: Firing:

Storage:

Lower limit ---------------------- -80°F (for periods not more than 3 days

Upper limit ----------------------- +141°F (for periods not more than 4 hr/day *Paclang -------------------------- 1 charge in metal container M13

*Container:

Dimensions ------------------------- 27-3/4 x 7-3/8 x

*NOTE: See DOD Consolidated Ammunition Catalog for complete packing data including NSN's.

DOT shipping class:

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