|
|
| U.S. EXPLOSIVE ORDNANCE |
| PART 1 - PROJECTILES, PROPELLANT, AND PROECTILE FUZES |
| Chapter 3 - PROJECTILE FUZES |
| Section 2 - POINT DETONATING FUZES FOR PROJECTILIES |
|
No. 253 Mks 1-3 |
|
Projectiles used in |
20-mm (Army) H.E.-I. Mk 1 |
|
Over-all length, inches |
1.41 |
|
Diameter at nose, inch |
0.32 |
|
Diameter at base ogive, inch |
0.70 |
|
Threaded length, inch |
0.12 |
|
Threads |
4 R.H. |
|
Weight, pound |
0.058 |
|
Material |
Brass |
|
Filling |
Detonator - mercury fulminate |
|
|
Relay charge - mercury fulminate |
| Booster - tetryl |
|
Description: This fuze is designed to function with instantaneous action on impact with light material surfaces. It is initiated on impact by the set-forward force of the de-tonator charge, or by pieces of metal from the body striking the detonator charge. |
|
The fuze consists of two major parts, a brass body with an air chamber in its forward part, and a brass magazine containing the explosive train and externally threaded (L.H.) to screw into the base of the body. The magazine is covered with a brass disc separat-ing the detonator from the air column. In the Point Detonating Fuze Mk 1, this disc is so-lid, but in the Mks 2 and 3 a small hole is drilled through the center of the disc to in-crease the fuze's sensitivity. In the Mks 1 and 2 the body cavity was closed at the for-ward end by a thin brass disc; in the Point Detonating Fuze Mk 3, the brass disc is omit-ted, and the nose is solid across this area. |
|
Remarks: The fuze contains no interruptors or other safety devices, and is therefore, sensitive for handling. |
|
Figure 88. Point Detonating Fuze No. 253 Mk 3 |
|
|
 |
