Disassembly of the Russian RPK 75 Round Drum Magazine

By Norman Potts

When Mikhail Kalashnikov first designed his famous AK-47, I doubt he had any idea as to the status his invention would attain. The Avtomat Kalashnikova is now found throughout the world in every major conflict, and has grown into several models manufactured by no less than seventeen countries. There are even derivative models, such as the Saiga rifles and shotguns, and a plethora of accessories available for this weapon that, after more than fifty years, is still very viable on today’s battlefield.

Sometime in the early 60’s, the Soviets adopted the Ruchnoi Pulemet Kalashnikova, or RPK . It is the squad automatic version of the AKM, with a heavier receiver and 23.2 inch heavy barrel. The RPK usually uses an extended 40-round version of the standard 30-round magazine, but the excess length often interferes with a good prone position, and 10 extra rounds do not really last that much longer at 600 RPM. The Soviets thus developed the 75-round drum magazine, which proved to be both more compact and extend firing time significantly.

The 75-round drum is a desirable accessory for almost any AK owner, and often has been quite expensive, especially in light of today’s political climate. The Soviet drum is often more expensive than the similar Chinese 75 and 100-round drums, and at one time was almost impossible to obtain. Both the Soviet and Chinese drums hang below the weapon and are somewhat heavy when fully loaded, but the Soviet drum has a bit more of a forward cant, which allows greater compactness when one goes prone. The major difference, however, is how they load and disassemble.

The Chinese drums are quite simple, in that one merely pops the retaining clips located at ten o’clock and two o’clock at the back of the drum, lifts off the hinged cover, ensures that the follower is at its innermost position, and places the rounds nose-first in the empty slots of the feed mechanism’s arms. The cover is then closed and secured, the key on the back cover wound about fifteen clicks (three if it will not be immediately used), and you are ready to rock and roll. To unload, one merely opens the back cover as before, pushes the button at the top of the spindle to release the spring tension, and dumps the rounds. The drum may also be cleaned at this point, as I know of no way to easily disassemble one for field cleaning.

There has been much misconception regarding the Soviet drum with respect to disassembly. I have been told by more than one person, and have even seen twice in this very publication, that the Soviet 75-round drum cannot be disassembled. This is incorrect.

Actually, the back cover can be removed, although it is difficult to do with a loaded drum, allowing the drum to be fully disassembled into its major components. A loaded drum may be emptied in this fashion, but one must hold the feed mechanism, which is under pressure from the spring, as the cartridges are dumped out. When all cartridges, including those in the neck of the magazine, are out, the mechanism can be allowed to unwind by maintaining control of the mechanism arms and main body of the magazine. This procedure is not recommended unless a stoppage necessitates it.

The Soviet drum is disassembled by taking a pointed object, such as a cartridge or a punch, and pushing in the detent at the center of the knurled knob on the back cover of the drum. (Fig 1) The knob is turned 90 degrees left or right, and the knob can be lifted off, followed by the back cover. Pressing again on the detent with the pointed object, one can lift up the small lever near the “T” and lift off the feed mechanism.

(Figs 2 & 3) You will notice that the head of the spindle is T-shaped where the knob mates to it. This completes the disassembly for cleaning the drum. There are five major components of the Soviet drum, making it very simple to clean and reassemble (Fig 4).

The drum is assembled in reverse order. The feed mechanism must be rotated clockwise in order to tighten the wound leaf-spring, which keeps tension on the rounds and ensures reliable feeding. All of the feed mechanisms I have seen in the Soviet drums have an arrow stamped into one of the arms, which indicates the direction in which the mechanism is rotated to create spring tension. I index the feed mechanism by positioning the arm with the arrow just ahead of the magazine neck. I then rotate the mechanism in the direction of the arrow until two more of the arms pass the same point. The three-round “feeder tab”, which acts as a follower, is placed into the neck and is pushed upwards by the mechanism. (Fig 5) The rear cover is then set in place and installing the knob completes re-assembly.

To load the Soviet drum, it is held by placing the right thumb on the side of the neck and the index finger is hooked on the lip of the loading lever.(Fig 6) The loading lever has a ratchet that rotates the feed mechanism inside the drum and allows the rounds to move into place between the arms of the mechanism. The left hand is used to insert cartridges into the neck of the drum. The method I use is a “two and three” pattern, in which I pull the lever up for each of two rounds and then push in three more without pulling the lever. This method has worked for me to prevent the rounds from jamming up as they move into place inside the drum, which is a possible problem with external-loading drums of this type. As always, it is best for each individual to use the method that suits himself.

Which of the two drums do I prefer? Like most similar things in life, they each have strengths and weaknesses. The Chinese drum can be loaded and unloaded with ease, but the Soviet drum cannot be accidentally opened and seems to be more robust and solid, as it is made of thicker metal. Although cartridges in the two drums appear to be organized in the same manner, the Chinese drum may actually feed a little more smoothly than the Soviet drum, due to the cartridges being more compartmentalized in the drum. The Soviet drum relies more on spirals in the front and rear interior of the drum to guide the cartridges up into the neck as the feed mechanism rotates. (As you can see in the lead photo) The Chinese drum can be stored fully loaded and the spring wound when ready, but I have found that, sometimes during firing, the spring might not be wound enough and one has to wind it up a few more clicks to feed the last few rounds. This does not happen with the Soviet drum. I have also kept my Soviet drum loaded for months and it functions just fine.

The Soviet drum has a carrier that is made of green rubberized fabric, with straps that are secured by aluminum studs which protrude through holes in them. The straps can be released by pulling upwards on the ends. The carrier I have is actually East German, but the drum is Soviet, as evidenced by the “star in shield” marking stamped near the neck of the drum. The drum can be used with the carrier in place by releasing the carrier from the belt and pulling off the cover on the neck.

The Chinese drum comes with a cotton olive-drab carrier that has a cloth shoulder strap, a side pouch for a cleaning kit or oiler, and is secured with those goofy loop-and-wood button closures that the Chinese seem to be so fond of. It appears to me that the drum must be removed from its carrier to be used, because, if nothing else, the shoulder strap hangs down when the drum is inserted into the weapon and the gunner’s enemy would probably die of laughter as he trips and falls with the strap tangled about his legs! Perhaps that’s what that side pouch is for.

I prefer the Soviet drum for its stronger construction, reliable function, ease of disassembly, and functional carrier, which also is not as likely to rot in more hostile climates. As stated before, it is also more prone-friendly due to its forward cant, whereas the Chicom drum hangs relatively straight down under the weapon. Both drums are heavy when fully loaded, and may not be practical for routine patrol with a standard AKM. For ambush situations or regular blasting, however, this is quickly remedied by proper application of the trigger finger. In either case, I highly recommend this desirable accessory for one of the world’s best combat weapons.