Combination Firing Device M1Tension and Release Fiirng Device M3
U.S. EXPLOSIVE ORDNANCE
PART 5 - MINES
Chapter 16 - FUZES AND FIRING DEVICES

Combination Fuzes M6 and M7

General: The combination fuzes M6 and M7 are designed for firing explosive charges either by means of a trip wire or by pressure. The mechanical construction of the fuzes is similar, but they differ in the loading of the base plug.

The M6 is 6.6 inches in length, and the threaded portion of the base is ½ inch long; the M7 is 7.13 inches in length, and the threaded portion of the base is ¼ inch long. The igniter charge of the Combination Fuze M6 consists of 10 grains of black powder, while the detonator of the M7 consists of a U.S. Army Special, Type A, blasting cap.

Description: The fuze consists of a head and case crimped together, which contain a trigger pin, a release pin, and a firing pin, each with a spring. A small groove in the firing pin is held in the narrow part of a keyhole slot in the release pin, the release pin being provided with a ring for attaching trip wires. The trigger pin has three one-inch-long prongs of stiff steel wire projecting from its head. A wedge is provided on the bottom of the trigger pin which enters a slot in the release pin. When sufficient pressure is applied to one or more prongs, the release pin is moved aside and the firing pin passes through the large opening of the keyhole slot. Two safety pins are provided, one passing through the firing pin and the other passing through the release pin. The base is a hollow cylinder which contains the primer

Use: The Combination Fuze M6 can be used in the Anti-Personnel Mines M2A1, M2A2, M2A3, or M2A3B2. The Combination Fuze M7 is used in the Anti-Personnel Min M3.

Operation: When the fuze is armed, either a pull on the release-pin ring of 6 to 10 pounds or a pressure of 10 to 20 pounds on the three prongs (10 to 30 pound on one prong), depressing the trigger pin 9/32 inch, will move the release pin 3/32 inch, so that the larger hole is in line with the firing pin. The firing pin is thereby released, and the compressed firing-pin spring will drive the striker down on the percussion cap.

Remarks: The Combination Fuzes M6 and M7 replaced the Combination Fuzes M2, M2A1, M3, and M3A1 in the Anti-Personnel Mines M2 and M3 Series.

Figure 251. Combination Fuze M6 (left) and Combination Firing Device M1 (right)

Combination Firing Device M1Tension and Release Fiirng Device M3