RKG-3 H.E.A.T. & UPG-8 Practice Hand Grenades
RKG-3 & UPG-8 RKG-3
Ruchnaya Kumulyativnaya Granata

("Hand Shaped Charge Grenade")

This grenade was developed by the Soviet Union during the Cold War and continues to be copied and produced by numerous countries.

It is a drogue stabilized, impact fuzed, hollow charge device, with a penetration performance of 125-165mm and a secondary fragmentation radius of about 20m.

The RKG-3 family of grenades vary in size ranging from 65-78mm in diameter, 350-388mm in length and holding 384-560g of explosive.

The H.E.A.T. grenade at left is an East German copy of the RKG-3. It measures 70mm X 360mm.

Next to it is the UPG-8 training counterpart, painted the characteristic black with a white stripe and lettering.

Instruction Text

The full text on the head translates:
Insert the detonator (booster) in the grenade.
Screw on the handle.
Pull the safety ring, throw the grenade with force against the target & take cover immediately.
It is forbidden:
To take apart the handle or to touch a dud grenade.

RKG-3 in Flight Grenade During Flight:
1-Stabilizer Spring        2-Moveable Tube        3-Guy Wires        4-Cloth Stabilizer
5-Pop-Off Cap            6-Cap Spring

Above Illustration from:
Nastavleniye po strelkovomu delu: ruchnyye granaty
Ministry of Defense of the USSR, 1974
RKG-3 Sectional
The internal mechanism is very complex and I believe the stabilizer is not reloadable if activated, at least not outside the factory.
In principal it is similar to others of its type. A detonator is inserted just before use, the grenade is grasped firmly, safety pin pulled and the grenade is throw high over the target. When released, the safety lever is free and releases a spring loaded stabilizing parachute, which keeps the nose pointed at the target. On impact a base fuze detonates the grenade.
The complex nature of the design is due to safety features incorporated into the grenade fuze to avoid premature detonation. Definitly one of the most complex grenade types made.

Uchebnaya Protivotankovaya Granata

("Training Antitank Grenade")

The training version is designed to be re-usable, and the mechanism inside the handle is quite different. Specialized tools were supplied that enabled the stablilizer to be reloaded in the field, but spare complete drouge units were issued as well for quicker reloading. The body is made of heavy sheet metal with gas escape holes to vent the practice charge.
Internal Comp
Shown here are the differences between the H.E.A.T. and training versions. Not the shape charge conical liner visible at left. You can see that only about 1/3 of the warhead volume contained explosive.

This grenade is only to be used from behind cover, as the average throwing range is only 15-20 meters.