[Lone Sentry: FM 17-76: Crew Drill and Service of the Piece, Medium Tank, M4 Series (105-mm Howitzer)]
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FM 17-76: Crew Drill and Service of the Piece, Medium Tank, M4 Series (105-mm Howitzer)
Field Manual, War Department, September 15, 1944
[DISCLAIMER: The following text is taken from a WWII U.S. War Department Field Manual. As with all field manuals, the text may be incomplete or inaccurate. No attempt has been made to update or correct the contents of the field manual. Any views or opinions expressed do not necessarily represent those of the website.]

Section X

44. GENERAL. a. The destruction of materiel requires a command decision and will be undertaken only on authority delegated by division or higher commanders. Destruction is ordered only after every possible measure for the preservation or salvage of the materiel has been taken, and when in the judgment of the person exercising the authority such action is necessary to prevent.

(1) Its abandonment in the combat zone.

(2) Its capture intact by the enemy.

(3) Its use by the enemy, if captured, against our own or allied troops.

(4) Knowledge of its existence, functioning, or exact specifications from reaching enemy intelligence.

b. The principles to be followed are—

(1) Methods for the destruction of materiel subject to capture or abandonment in the combat zone must be adequate, uniform, and easily followed in the field.

(2) Destruction must be as complete as available time, equipment, and personnel will permit. If thorough destruction of all parts cannot be completed, the most important features of the materiel should be destroyed, and parts essential to the operation or use of the materiel which cannot be easily duplicated, should be ruined or destroyed. The same essential parts must be destroyed on all like units to prevent the enemy from constructing one complete unit from several damaged ones by "cannibalism".

c. Crews will be trained in the prescribed methods of destruction, but training will not involve the actual destruction of materiel.

d. (1) The methods outlined in the paragraphs below are given in order of effectiveness. If method No. 1 cannot be used, destruction should be accomplished by one of the other methods in order of priority shown. Adhere to the sequences.

(2) Certain methods require special tools and equipment, such as TNT and incendiary grenades, which normally may not be items of issue. The issue of such special tools and material, the vehicles for which issued, and the conditions under which destruction will be effected are command decisions in each case, according to the tactical situation.

45. DESTRUCTION OF HOWITZER. Remove sights. If evacuation is possible, carry the sights; if evacuation is not possible, thoroughly smash all periscopic sights and the telescope.

a. Method No. 1. (1) Open drain plugs on recoil mechanism, allowing recoil fluid to drain. It is not necessary to wait for the recoil fluid to drain completely before firing the howitzer as in (4) below.

(2) Place an armed (safety pin removed) antitank grenade, HE, or armed (safety pin removed) antitank rocket in the tube about 6 inches in front of, and with the ogive nose end toward, the HE shell in (3) below.

(3) Set fuze on an HE shell at "superquick", insert shell in the piece and close the breech.

(4) Attach a piece of string to the howitzer firing linkage in such a way that it may be fired by pulling the string. Dismount from the tank (down to the left rear) and fire the piece. Elapsed time: Approximately 2 to 3 minutes.

b. Method No. 2. Insert from three to five 1/2-pound TNT blocks in the bore near the muzzle, eight to ten in the chamber. Close the breechblock as far as possible without damaging the safety fuze. Plug the muzzle tightly with earth to a distance of approximately 11 inches from the muzzle. Detonate the TNT charges simultaneously.

c. Method No. 3. With another gun, fire HE, HEAT or AP projectiles at the tube of the piece until it is rendered useless.

d. Method No. 4. Insert four unfuzed M14 incendiary grenades, end to end, midway in the tube at 0° elevation. Ignite these four grenades with a fifth equipped with a 15-second Bickford fuze. The metal from the grenades will fuse with the tube and fill the grooves. Elapsed time: 2 to 3 minutes.

46. DESTRUCTION OF MACHINE GUNS. a. Method No. 1. (1) Caliber .30 machine gun. Field strip. Use barrel as a sledge. Raise cover until vertical; smash cover down toward front. Deform and break backplate; deform T-slot. Wedge lock frame, back down, into top of casing between top plate and extractor cam; place chamber end of barrel over lock frame depressors and break off depressors. Insert barrel extension into back of casing, allowing the shank to protrude; knock off shank by striking with barrel from the side. Deform and crack casing by striking with barrel at side plate corners nearest feedway. Elapsed time: 2 1/2 minutes.

(2) Caliber .50 machine gun. Field strip. Use barrel as a sledge. Raise cover; lay bolt in feedway; lower cover on bolt; smash cover down over bolt. Deform backplate. Wedge buffer into rear of casing allowing depressors to protrude; break off depressors by striking with barrel. Lay barrel extension on its side. Hold down with one foot, break off the shank. Deform casing by striking side plates just back of the feedway. Elapsed time: 3 1/2 minutes.

b. Method No. 2. Insert bullet point of complete round into muzzle and bend case slightly, distending mouth of case to permit pulling of bullet. Spill powder from case, retaining sufficient powder to cover the bottom of case to a depth of approximately 1/8 inch. Re-insert pulled bullet, point first, into the case mouth. Chamber and fire this round with the reduced charge; the bullet will stick in the bore. Chamber one complete round, lay weapon on ground, and fire with a 30-foot lanyard. Use the best available cover, as this means of destruction may be dangerous to the person destroying the weapon. Elapsed time: 2 to 3 minutes.

c. Small arms. Small arms cannot be adequately destroyed by firing with the bore stuck in the ground, with or without a bullet jammed in the muzzle.

d. Machine gun tripod mount, caliber .30 M2. Use machine gun barrel as a sledge. Deform traversing dial. Fold rear legs, turn mount over on head, stand on folded rear legs, knock off traversing dial locking screw, pintle lock, and deform head assembly. Deform folded rear legs so as to prevent unfolding. Extend elevating screw and bend screw by striking with barrel; bend pintle yoke. Elapsed time: 2 minutes.

47. DESTRUCTION OF TANK. a. Method No. 1. (1) Remove and empty the portable fire extinguishers. Smash the radio (paragraph 52). Puncture fuel tanks. Use fire of caliber .50 machine gun, or a cannon, or use a fragmentation grenade for this purpose. Place TNT charges as follows: 3 pounds between engine oil cooler and right fuel tank; 2 pounds under left side of transmission as far forward as possible. Insert tetryl nonelectric caps with at least 5 feet of safety fuse in each charge. Ignite the fuses and take cover. Elapsed time: 1 to 2 minutes, if charges are prepared beforehand and carried in the vehicle.

(2) If sufficient time and materials are available, additional destruction of track- laying vehicles may be accomplished by placing a 2-pound TNT charge about the center of each track-laying assembly. Detonate those charges in the same manner as the others.

(3) If charges are prepared beforehand and carried in the vehicle, keep the caps and fuses separated from the charges until used.

b. Method No. 2. Remove and empty the portable fire extinguishers. Smash the radio (paragraph 52). Puncture fuel tanks (see a (1) above). Fire on the vehicle using adjacent tanks, antitank or other artillery, or antitank rockets or grenades. Aim at engine, suspension, and armament in the order named. If a good fire is started, the vehicle may be considered destroyed. Elapsed time: About 5 minutes per vehicle. Destroy the last remaining vehicle by the best means available.

48. DESTRUCTION OF AMMUNITION. a. General. (1) Time will not usually permit the destruction of all ammunition in forward combat zones.

(2) When sufficient time and materials are available, ammunition may be destroyed as indicated below. At least 30 to 60 minutes may be required to destroy adequately the ammunition carried by combat units.

(3) In general, the methods and safety precautions outlined in Chapter 4, TM 9-1900, should be followed whenever possible.

b. Unpacked complete round ammunition. (1) Stack ammunition in small piles. (Small arms ammunition may be heaped.) Stack or pile most of the available gasoline in cans and drums around the ammunition. Place on pile all available inflammable material such as rags, scrap wood, and brush. Pour the remaining available gasoline over the pile. Sufficient inflammable material must be used to insure a very hot fire. Ignite the gasoline and take cover.

(2) Destroy 105-mm ammunition by sympathetic detonation, using TNT. Stack the ammunition in two stacks about 3 inches apart, with fuses in each stack toward each other. Place TNT charges between the stacks. Use 1 pound of TNT per four or five rounds of ammunition. Detonate all charges of TNT simultaneously from cover.

c. Packed complete round ammunition. (1) Stack the boxed or bundled ammunition in small piles. Cover with all available inflammable materials, such as rags, scrap wood, brush, and gasoline in drums or cans. Pour gasoline over the pile. Ignite the gasoline and take cover. (Small arms ammunition must be broken out of the boxes or cartons before burning.)

(2) (a) The destruction of packed complete round ammunition by sympathetic detonation with TNT is not advocated for use in forward combat zones. To insure satisfactory destruction involves putting TNT in alternate cases or bundles of ammunition, a time-consuming job.

(b) In rear areas or fixed installations, sympathetic detonation may be used to destroy large ammunition supplies if destruction by burning is not feasible. Stack the boxes, placing in alternate boxes in each row sufficient TNT blocks to insure the use of 1 pound of TNT per four to five rounds of 105-mm ammunition. Place the TNT blocks at the fuse end of the rounds. Detonate all TNT charges simultaneously. See FM 5-25 for details of demolition planning and procedure.

d. Miscellaneous. Grenades, antitank mines, and antitank rockets may be destroyed by the methods outlined in b and c above for complete rounds. The amount of TNT necessary to detonate these munitions is considered less than that required for detonating artillery shells. Fuses, boosters, detonators, and similar material should be destroyed by burning.

49. FIRE CONTROL EQUIPMENT. Fire control equipment, including optical sights and binoculars, is difficult to replace. It should be the last equipment to be destroyed. If evacuation of personnel is made, all possible items of fire control equipment should be carried. If evacuation of personnel is not possible, fire control equipment must be thoroughly destroyed as indicated below.

a. Firing tables, trajectory charts, slide rules and similar items should be thoroughly burned.

b. All optical equipment that cannot be evacuated will be thoroughly smashed.

50. RADIO EQUIPMENT. a. Books and papers. Instruction books, circuit and wiring diagrams, records of all kinds for radio equipment, code books, and registered documents will be destroyed by burning.

b. Radio sets. (1) Shear off all panel knobs, dials, etc., with an ax. Break open the set compartment by smashing in the panel face, then knock off the top, bottom, and sides. The object is to destroy the panel and expose the chassis. On top of the chassis, strike all tubes and circuit elements with the ax head. On the under side of the chassis, if it can be reached, use the ax to shear or tear off wires and small circuit units. Break sockets and cut unit and circuit wires. Smash or cut tubes, coils, crystal holders, microphones, earphones, and batteries. Break mast sections and break mast base at the insulator.

(2) When possible, pile up smashed equipment, pour on gas or oil, and set it on fire. If other inflammable material, such as wood, is available, use it to increase the fire. Bury smashed parts.


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