2.36in M6A5 or repainted practice M7A6 without fins shroud (missing) could match (with new waterproof safety pin).
The 2.36 inch A/T Rockets M6A1 and M6A3 are identical except for difference in the olive and the tail assembly. In other respects the two rockets are similar, consisting of a hollow olive crimped onto the body, a body union fitting into the base of the body with internal threads to receive the motor, and a fuze which is located in the forward end of the motor tube. The M6A1 has a conical olive, whereas the M6A3 has a hemispherical olive which gives better penetration by forming a stronger standoff piece for the shaped-charge effect of the explosive. M6A4 is like the M6A3, except that it is lighter - being made of high strength alloys and also uses the bore safe fuze M400. The M6A5 uses the bore safe fuze M401 and has a larger propellant grain, which eliminates the safety disk.
The M6A1 has six fins (5 1/2 inches long) spot welded to the nozzle, a steel cup internally threaded at the forward end to screw onto the motor tube. The M6A3 has a different type of tail assembly to obtain fin area and counteract the change of the center of gravity effected by the hemispherical nose. This tail assembly consists of four sheet-steel fins 2 5/16 inches long, each of which is curved over an arc of 90 degrees on its outboard edge to form a blade. Each fin is joined to the other by welding, with an overlap of approximately 1/2 inch to form a circular drum which is actually nothing more than a continuation of the four fins. The bases of the fins are spot-welded to the nozzle. In the M6A5 and
M7A6 the free end of the ignition wire is attached to the shroud tail by a chip-board disk, instead of the tape on earlier models.
The propellant consists of five sticks of ballistite. On an average, the propellant weighs approximately 61 1/2 grams, though it is loaded not by weight but rather by length of powder stick, to keep the pressure for various rounds at a relatively constant value. The M6A4 and M6A5 use the Powder M7, which burns at a lower temperature, +120° to -40° F.
The fuze for the M6A1 and M6A3 consists of a steel filing pin which slips into the central cavity of the fuze body, where it is held in a rearward position by the firing-pin spring. A circumferential groove midway down the length of the firing pin receives the safety pin, which extends through the motor tube. When the safety pin is removed, the firing pin is free to move forward, restrained only by the action of the firing-pin spring. After the safety pin has been removed, the firing pin will overcome the spring and detonate the rocket if it is dropped over four feet. The fuze body contains the Detonator M18 of
lead azide and
tetryl, and the booster charge of tetryl.
The practice rounds are similar to their accompanying service rounds. except that they are inert-loaded and have a dummy fuze or steel weight to fill the empty fuze space. The M6A5 and M7A6 have plastic closing plugs, making them waterproof rounds. They also use the Powder M7, which burns at a lower temperature, +120° to -40° F.
