The RPG-7 System Primer
4) As the grenade leaves the RPG tube, it has been “boosted” out by the expeller charge. Forward motion allows the four stabilizer fins to extend out to the sides, and it is important to remember this when firing as there must be at least 8 inches of clearance above all obstacles in the flight trajectory. This is also a good time to point out another reason not to install the expeller cartridge onto the rocket and carry it around for a long period. If this is bent or damaged then the entire trajectory may be thrown off. The pyrotechnic pellet will burn through to ignite the rocket booster, as long as the spring held block is out of the way due to proper forward momentum. Propellant gases begin the booster action at 11 meters from leaving the tube of the launcher. (See note 1)
5) The rocket motor burns and the gases push forward into the nozzle block expansion chamber at the front joint just behind the grenade body. This chamber has six holes that point to the rear and outward, and the pressure from the gases blows out the seals and the six holes drive the grenade assembly forward during its assisted flight. This event leaves a puff of smoke – sometimes observed as a smoke “ring” – 10 to 15 meters in front of the operator. If the target has an oblique view of the RPG-7 operator, this will be visible as a separate event, making locating the RPG-7 position easy for return fire. It is important to note that the holes are canted in a direction opposite that of the rotation imparted by the fins. The spin rate imparted by the four fins is slowed after rocket ignition. This prevents over-spin and reduces spin degradation of the shaped charge on firing. Just behind the nozzle block is an elastic ring that holds the RPG-7 round in the launcher so slight downward firing is possible without the round coming forward and misaligning the primer and firing pin. When the rocket burns out, forward momentum keeps the grenade airborne until it reaches a target or approximately 900 meters where the safety fuze causes the nose cone area to explode. This does activate the shaped charge, although this author has observed many RPG-7 rounds that reached the five second mark, the safety detonated, and the shaped charge was still somewhat intact leaving energetic material on the ground.
6) Cutaway view of the shaped charge. The piezo-electric nose fuze fires a spark plug system at the rear of the shaped explosive content. As the detonation wave moves through the explosive, the tin coated copper cone at the center is transformed to a high-speed, high temperature jet (actually a “warm solid”) of metal that penetrates up to 13 inches of steel armor.
Although one operator can certainly load and fire an RPG-7, training and combat firing the RPG-7 series of weapons is considered a two man operation: the operator and assistant gunner. Both should be proficient with the system and should have a lot of live fire training. The skills needed to hit a target with an RPG can not be gained from simple training drills, especially firing at longer ranges. When the RPG team is “hunting,” it is just as important to figure in attempting to conceal their position and the back-blast signature from the enemy as it is to find good front cover. In the case of needing a second shot, the back-blast will frequently have located them for the enemy. Aiming so that the rear of the RPG-7 is pointed around the corner of a large building or hill can help with this. A couple of safety points should be emphasized. Behind the tube, for about 30 meters, there is a 70 degree danger zone. Close to the tube is a kill zone. The operator and his A-gunner should always be ensuring that there are no obstacles, walls, etc within 2 meters behind the RPG. Good advice would be to make that at least 3 meters. Back-blast can be quite deadly. Firing from inside a small room is to be discouraged. We at Long Mountain Outfitters have been told that there exists a video clip of an Iraqi insurgent firing an RPG-7 from a third floor window with the back-blast hurling him forward out the window. If you have this clip, please forward it to us. It contains sage wisdom for all potential operators.
The operator and A-gunner will have worked together and developed their own method of communicating these sequences but it is frequently taught for the A-gunner to be on the left of the operator and reach across to load. This may not always be practical, but it is part of many countries’ training doctrine. This author believes that the A-gunner should be on the right of the operator. Using today’s quality range finders is very important, as accurate range distance should increase first round hit probability. Once the pair have stalked their target, found range and target speed, and set up the firing position, the following sequence of events should occur:
• A-gunner visually clears the tube, then prepares the rounds to be fired, attaching the expeller charges as needed.
• Operator ensures the push through safety is to the right and the hammer is not cocked, then announces “Load”.
• A-gunner loads a round into the tube, ensuring the index is properly occurring and the elastic gasket is snugly in place holding the round in the tube, then visually examines the back-blast area for friendlies and extremities, to ensure there is no danger to the rear, and to ensure that various and assorted Operator and A-gunner appendages are out of the blast area. He announces “Clear to fire”.
• Operator announces “Ready” and the A-gunner removes the fuze protector (this may have been done before loading). A-gunner resumes watching back-blast area for friendlies and gives warning to the operator if the situation changes.
• Operator cocks the hammer, takes careful aim, pushes the safety to the left, then, squeezing the trigger, he fires. The operator then analyzes shot effect and decides whether to reload and repeat, or to depart the area with all due haste.
• In the event of a misfire, the operator announces “Misfire,” then pushes the safety to the right and “On,” announces “Safe” and the A-gunner makes a fast visual inspection to see if the grenade was properly indexed or not. High probability in a misfire will be that the grenade was not properly seated. If that is the case, the A-gunner then immediately reseats the grenade and initiates checks. Operator fires again. If the grenade was in place, then the A-gunner should pull the grenade forward and visually inspect the primer for a hit. If no hit, try again. If there is a dented primer, then the grenade should be gingerly moved away from the area and left for EOD (on the range) or blown in place at the first opportunity if in the field.