US Bomb, 25 lb Practice, Mk 76 Mod 1

1789-357

Description

The 25-lb PB Mk 76 Mod 0, now obsolescent, has a tear-drop shaped, cast-metal body which is centrally bored. The tail-tube assembly fits into the end of the bore. The conical afterbody covers the tail-tube assembly and is threaded to the body. The two sections are staked together to prevent unscrewing. The fin assembly is welded to the tail tube. Firing Pin Assembly Mk 1 Mod 0 and the signal are assembled into the bore of the body and secured in place by a safety cotter pin.

In the Mod 0 a single lug is positioned just forward of the center of gravity of the bomb. Some bombs of early manufacture have a suspension lug with a small opening which precludes use of the bomb on Shackle Mk 8 All Mods or Aero 14 and 15 series racks. Later manufacture provided lugs with a larger opening that permits use on this type shackle or rack. Activities may replace the older type lugs with lugs having the larger opening. The threads in the bomb body should be cleaned after the smaller lug is removed. Glycerine litharge cement should be applied to the threads to hold the newer type lug in position.

The Mod 1 is designed for air-burst firing only. The Time Fuze AN-M146E3 is used to fire the Signal Mk 4 Mod 3 which is seated in the bore of the body section. A setscrew is threaded into the nose of the bomb to retain the fuze and signal. Smoke produced from the detonated signal is discharged rearward through the tube of the fin assembly.

In the Mod 1 a single suspension lug is threaded into the bomb body just forward of the center of gravity and cemented in place. Two 3/8 inch indexing holes are drilled into the body to assist in the proper positioning of the bomb in the Aero 8A Practice Bomb Container.

The Mod 2 is similar in appearance and functioning to the Mod 0 except that two 3/8 inch indexing holes are drilled into the body at the center of gravity to assist in the proper positioning of the bomb in the Aero 8A Practice Bomb Container.

See Also

Nothing else to see.

Source(s)

Collaborative Ordnance Data Repository

OP 2216, Volume 1 - Aircraft Bombs, Fuzes, and Associated Components (1960)

OP 1280, Aircraft Bombs (1955)