Description
M86 series propelling charges are used in the 175mm M107 Self-Propelled Weapon System.
(Ancillary items used only with these charges are the M1 additive jacket and the M5 flash reducer described below.)
The charge is an adjustable three increment white bag type. It is approximately 49-1/2 inches long and contains a total of 55 pounds of multi perforated Propellant M6 in acrylic viscose-rayon bags. The bags are tied together by four tying straps attached to the top of Increment 1 and knotted on top of Increment No. 3. The tying straps are reinforced by cord tied tightly around the junction of Increments No. 2 and 3. Each propelling charge has an igniter core assembly extending through the center of the charge, The core assembly consists of three rigid polyurethane tubes containing bagged igniter cores of black powder. The igniter tubes for Zones 1 and 3 contain bell shaped ends which assemble over the ends of the igniter tube in Increment 2. A red cloth igniter pad, filled with black powder, is sewn to the base of Increment 1. The igniter core for Increment 1 is sewn to the igniter base pad and is loose in the Increment 1 igniter tube. The cores for Increments 2 and 3 are tied inside the igniter tubes for these increments. An igniter protective cap is placed over the igniter base pad for protection in shipment and storage. An additive jacket is issued separately for assembly over Increment 3 when firing full charge. (The majority of M86A2 charges are shipped with the additive jacket already assembled over Increment 3.) All charges are packed with an M82 percussion primer. An M5 flash reducer is also issued separately to be assembled around the junction of Increments 2 & 3 on certain M86A1 charges, It is designed to reduce excessive blast and flash effects associated with certain lots of Propelling Charge M86A1. The flash reducer, which contains 16 ounces of potassium sulphate, is an apron-type cloth bag designed to be tied around the forward end of Increment No. 2 with its leading edge at the junction of Increment No. 2 and 3.
Bore wear reducing Additive Jacket M1 is used with Increment No, 3 when firing M86 Series Propelling Charges at full charge, It consists of two 10 1/2 x 18 x 1/8 inch cloth backed sheets of additive mixture stitched together. The additive mixture is composed of 47 percent titanium dioxide and 53 percent wax. The cloth backing, which is bonded to and overlaps the sheets of additive mixture, is stitched to an unbended tough plastic film casing which serves as a jacket liner. When compressed along the seams, the jacket arches to form a cylinder with a diameter of approximately 7-1/2 inches.
The M86 has a 4 ounce igniter pad and all 3 tubes are perforated. The M86A1 has a 2 ounce igniter pad and an unperforated Increment No. 1 tube. The M86A2 is identical to the M86A1 except for the igniter tubes, which are reinforced with dacron scrim. Early production M86A2’s are packed without additive jackets.
Functioning
No information about functioning.
Hazardous Components
No information about hazardous components.
See Also
Source(s)
TM 43-0001-28, Artillery Ammunition (chg 11, 2003)
TM 9-1300-203, Artillery Ammunition (1967)
