1. Construction. The 10-lb. HC Smoke Bomb M77 consists of a steel hexagonal case 2.87 inches across the flats and 19.5 inches long, weighing approximately thirteen pounds when filled. This bomb has no device for stabilization in flight, and therefore uses the "all-ways" type Fuze M150. Components of the bomb are as follows:

(a) Body - a sheet steel leak-proof casting extending the entire lenght of the bomb (Fig. 8).

(b) Tail Cup - A tail cup fits into the rear of the casing, having a dome which in turn houses the fuze.

(c) Filling - The bomb is filled with 9.5 pounds of Typ "C" HC smoke mixture (Heaxchlor-ethane-zinc oxide-aluminum mix).

(d) All-ways Fuze M150 (Fig. 9) - This is an all-ways action type fuze. The body and head are zinc alloy castings. This fuze incorporates the primer M26. The booster cup is made of zinc alloy and is filled with a starter mixture.

Figure 7 - View showing side of 100-lb. Cluster E44 (quick-opening)
made up of 14 HC Smoke Bombs M77

2. Operation. A retaining pin is removed from the fuze when the fuzed bombs are as-sembled in the cluster. While the bombs are in the cluster, their proximity holds a relase clip to the body of the fuze. When the bombs are released, the arming pin and release clip are forced out by the arming pin spring, permitting the safety pin to enter the cavity in the striker. Impact forces the striker and sleeve together, piercing the primer, which in turn ignites the first fire mixture, which ignites the HC smoke mix. The heat generated by the burning of the first fire mixture and the HC smoke mix melts the zinc alloy fuze body. The smoke is the emitted through the fuze hole in the tail cup. Caution: Once the arming pin jumps out, the fuze is armed and any attempt to reinsert it may cause the fuze to fire.

3. Painting and Marking. The 10-lb. Smoke Bomb M77 is painted blue gray overall with a ½-inch yellow band 6 13/18 inches form the tail. On one flat surface the symbol of fil-ling, the designation, loader's initial or symbol, date of filling (month and year) and loa-der's lot number are stenciled in 3/8-inch yellow marking ink.

Figure 8 - 10-lb. HC Smoke Bomb M77

Figure 9 - M150 All-Ways Fuze