20-mm Model 3 Impact Fuze25-mm Model 1 Fuze
Japanese Explosive Ordnance – Army Ammunition – Navy Ammunition
Chapter 5 - Section 4
NAVY PROJECTILE FUZES
20-mm Two-Piece Fuze
Use: 20-mm projectiles.
Over-all length (with gaine): 1 1/8 inches.
Over-all length (without gaine): 15/16 inch.
Maximum diameter: 23/32 inch.
Threaded length: 3/16 inch.
Number of threads: 5.

Construction: A black steel nose section threads onto the brass body. The top of the air column is closed by a thin brass cap held between the nose section and the fuze body. Two spanner holes are present in the fuze body.

Operation: The fuze has no safety or arming features. On impact, the nose is crushed and the compression of the air in the air column detonates the gaine.

Figure 430 – 20-mm Two-Piece Fuze.

20-mm Model 3 Impact Fuze25-mm Model 1 Fuze