Part 5 - Hand and Rifle Grenades; Chapter 3: A./T. Hand Grenade No. 75 Mks I, II, and III (Service)Part 5 - Hand and Rifle Grenades; Chapter 4: Smoke Hand Grenade, W.P. No. 77 Mks I and II (Service)
BRITISH EXPLOSIVE ORDNANCE
Part 5 - Chapter 3
Anti-Tank Grenades

A./T. Rifle Grenade No. 85 Mks I, II, and III (Soon as Service)
Data

Over-all length

 10½ in.

Diameter

 1 7/8 in.

Total weight

 1 lb. 6 oz.

Filling

 RDX/TNT 50/50

Filling weight

 4½ oz.

Fuzing

 No. 430 Mk I and No. 431 Mk I

Delay

 None

Description: The Grenade No. 85 is an anti-tank, cavity-charge grenade patterned after the U.S. Army M9A1 and similar in construction. The Mk I is fitted with Fuze No. 430 Mk I, which will function satisfactory on impact up to 45° from the normal. There is no safety pin to withdrawn, and the fuze does not arm until the grenade is fired. The Grenade Mk II has the same head but is fitted with Fuze No. 431 Mk I, which differs from the Fuze No. 430 in that it has a longer booster, and is easier to assemble and inspect.

The Grenade No. 85 Mk III is similar to the Mk I except for the fact the lower body is wire wrapped to increase fragmentation, allowing a dual employment as either an anti-tank or anti-personnel grenade. The tail tube and fuze are made of a light alloy in the Grenade Mk III. This change of material gives the  fuze the designation No. 431 Mk I/I.

Operation: Upon firing, the diaphragm is reversed by gas pressure, forcing the arming spindle forward. This permits the locking ball to slip into the groove in the arming spindle, thus freeing the striker, which is held away from the cap by the creep spring. Upon im-pact, the striker compresses the creep spring to fire the cap, the booster, and the main filling.

Figure 243 – A./T. Rifle Grenade No. 85 Mk I

Part 5 - Hand and Rifle Grenades; Chapter 3: A./T. Hand Grenade No. 75 Mks I, II, and III (Service)Part 5 - Hand and Rifle Grenades; Chapter 4: Smoke Hand Grenade, W.P. No. 77 Mks I and II (Service)