The RPD Machine Gun: 4 Big Things You Must Know

The RPD machine gun has a rich and interesting backstory. Many people are aware of the weaponry introduced in the Vietnam War, however, very few of these weapons ultimately wound up to be classics. The RPD is one of those few.

Both the United States and S. Vietnamese soldiers relied heavily on the M16 assault rifle and M60 machine gun. North Vietnamese, on the other hand, favored the SKS-45 carbine and the AK-47, created by Sergei G. Simonov and Mikhail T. Kalashnikov, respectively. 

For backup, the N. Vietnamese often turned to Vasily A. Degtyaryov’s RPD. For those unaware, the RPD machine gun actually goes all the way back to 1921, when Degtyaryov began his work on a gas-powered machine gun. The Red Army would eventually adopt the RPD 7 years later in 1928.

In an attempt to create lighter, more compact weaponry, Degtyaryov and his team went to work on designing a gun that could house the 7.62×39 short-case cartridge. This lighter ammo could make all the difference in the size and weight of their guns.

Work began in 1943 but was eventually slowed down due to the war. But by ’45, the DPM was finally complete. Although it wasn’t around long enough to see much action, the Soviet Union would ultimately adopt the DPM, as would its allies.

This continued until the 1960s when the DPM was replaced with a new, handheld machine gun from Degtyaryov known as the RPD machine gun. Short for “Ruchnoy Pulemyot Degtyaryova”, this belt-fed machine gun was gas-operated and had a locking system, not unlike its WWII predecessor.

Thanks to continuous 50-round ammunition belts, rounds could be linked together, making the RPD capable of firing 100 continuous rounds of ammunition. At just a little over 15 pounds, the RPD was significantly lighter than the M60’s 23-pound weight.

In this article we’ll cover all the key aspects of the RPD machine gun, but in particular, we’ll look at the following 4 elements:

  1. Versions of the RPD
  2. Ergonomics
  3. The Drum Magazine
  4. Operation of the RPD

1. Practice Makes Perfect – The RPD Machine Gun Variants

The Soviet Union worked hard to improve on the RPD machine gun, ultimately succeeding in five unique weapons. The first variant was equipped with a female gas piston that fitted onto a male gas spigot. There wasn’t a dust cover. However, you would find a reciprocating cocking handle, along with a windage knob that was located on the right portion of the rear sight.

The second version of the RPD machine gun had a male gas piston that fitted onto a female cylinder. Also different from the first variant was the location of the windage knob. This time, it was changed to the left portion of the rear sight. 

For the third version, a dust cover was finally added to the feeding mechanism. The cocking handle was changed, as well. This time, it was a non-reciprocating folding cocking handle. This version of the RPD machine gun would eventually be the model for the Chinese Type 56.

The fourth variant, often referred to as the RPDM, came with an extended gas cylinder and a friction roller located on the piston side, as well as a buffer within the butt. 

And lastly, a fifth model was introduced that featured a folding cover belt on the feeding mechanism. There was also the addition of a cleaning rod located in the butt trap. The Chinese would once again base one of their weapons, the Type 56-1, off of this gun.

Initial reports of RPDs came in from both American and S. Vietnamese forces in 1964. These reports coincided with initial encounters had by N. Vietnamese Army soldiers. With more RPDs making their way into the hands of the Viet Cong, this machine gun would soon become the principal weapon used by them.

With so many variants ultimately produced in the following years, there is little doubt as to the impact the RPD machine gun had.

Although mostly fired as a support weapon in fixed positions, the RPD’s light body served to allow operators to hold it like that of an automatic rifle. It could even be used for anti-aircraft weaponry if necessary.

Using the same rounds as those used in the AK-47 certainly had its benefits. For one, this simplified logistics for communist forces, especially when you consider the fact that the United States and S. Vietnamese soldiers were still using 5.56mm rounds (M16s) and 7.62mm ammo (M60s).

As one of the most feared weapons in all of Vietnam, it’s little wonder as to why the RPD machine gun has such a storied history. Let’s take a moment to explore the basics of this fabled weapon to better understand its legendary performance on the battlefield. 

2. The Ergonomics of the RPD

Thanks to Degtyaryov’s stellar engineering feats, his weaponry was largely considered to be far superior to any other at that time in history. As such, this made the RPD machine gun an intelligently crafted gun, no matter how you look at it.

The RPD was incredibly well-balanced. Equipped with both top and bottom handguards, it was a comfortable weapon to fire. And since the handguards were made of wood, soldiers found that they could easily fire for extended periods of time without the fatigue brought on by similar weaponry.

The RPD machine gun could certainly be fired from the hip in an assault position. But this often meant at the risk of burning one’s hand. What’s more, if the RPD was fired continuously for too long, the wooden handguards could potentially catch on fire. 

It’s not a stretch to venture that many soldiers firing the RPD devised clever ways to wrap the handguards so as to avoid accidental burning or fire. Doing so would certainly allow the RPD to be fired from various positions without issue.

It’s important to note that firing the RPD machine gun offhand and with a heavy drum mag would prove to be extremely challenging. If using a sling, however, this is made to be much easier. 

The buttstock on the RPD machine gun is quite heavy, providing an excellent buffer when firing. Similar to Degtyaryov’s earlier DP light machine gun, the RPD boasted a unique square shape that made it immediately recognizable to all who were privy to its design.

As such, those familiar quickly discovered various firing techniques to employ via the RPD. If one was familiar with European machine gun techniques, the RPD machine gun could be cupped from below the buttstock, resulting in greater support while firing. 

Many will argue that the pistol grip is oddly shaped and, thus, uncomfortable. However, implementing other firing techniques served to remedy this issue, making the RPD more comfortable and, therefore, more manageable. 

It would no doubt be of great benefit for operators to learn various machine gun firing techniques, as this would serve to give them the edge on the battlefield when wielding the RPD. Extensive training is an absolute must for anyone wanting to take full advantage of the RPD. 

3. The Drum Magazine

Circling back to the drum magazine, if you recall, the RPD machine gun can accommodate 100 rounds of continuous ammunition if needed. Fifty-round starter belts are equipped with loading tabs that let the gun be loaded without the need for an operator to open the cover. 

When joining belts together, the links must first be matched up. A loose cartridge can then be inserted into the feeding mechanism. The hooking section on the bottom must be snapped into the cartridge extractor groove.

Whenever a cartridge is inserted into the links, the two 50-round belts lock together and into place. For soldiers unfamiliar with loading 100-round belts of ammunition, this would often prove to be a difficult task. Much practice and dedication are needed to get the loading process down to a science. Any delays or mess-ups could spell certain doom for the operator. As such, there needed to be sufficient training in this procedure before being turned loose. 

If a team had access to a special loading machine, however, this would be a moot point. The loading machine negated the frustrating loading procedure and significantly increased the loading time.

An interesting aside about the RPD is that it rattles loudly when the drum is loaded. This may have been an issue for soldiers carrying the RPD machine gun through the bush. To load the drum on the RPD, a dovetail needs to be slid into a connection under the receiver. Later models, however, would attach the drum via the ejection port’s dust cover by simply snapping the mounting bracket into place.

United States Navy SEALs were known to use RPD machine gun drums that they captured from the enemy. They would separate these rounds to their Stoner light machine guns. This was likely due to the fact that the RPD’s drum mag consisted of smarter, more durable construction. Other variations were made of cardboard and could be rather aggravating to work with, especially when under pressure.

4. Operating the RPD Machine Gun, Step by Step

The RPD machine gun is known for firing from an open bolt. It also features a locking system that is similar to that used by Degtyaryov’s DP-DPM light machine gun, which was later modified to the Kjellman Frijberg locking system.

Operating the gas-powered RPD machine gun works as follows: When the trigger is pulled, a compressed recoil spring becomes unlocked. This allows the slide assembly to move forward, further powered by the RPD’s expanding recoil spring.

This is followed by the slide assembly riding in milled slots located in the receiver. This causes a round to become stripped and loaded into the RPD’s chamber. The bolt is then stopped forward, causing the extractor to position over the round.

This leads to the bolt becoming locked into the slide, which in turn continues to move forward, thereby engaging two locking lugs. The rear of the bolt then causes the firing pin to strike. Expanded gases are then forced during the firing process that travels through the gas port. 

This drives the gas piston and slides toward the rear. Unlocking of the bolt is delayed, causing the locking lugs to press against the bolt. The slide finally drives backward, causing the ejector to expel the cartridge from the chamber. 

Now that you understand the history and basic elements of the RPD, we’ll look at how to actually use one. This will be useful if you own one yourself, or if you are considering acquiring one. One thing to remember, of course, is that since it’s a machine gun, the RPD is an item that falls within the bounds of the National Firearms Act, and you must have an NFA tax stamp if you own one. If you don’t it is considered a felony. 

With that being said, let’s dig in!

How to Load and Fire the RPD

  1. A loaded drum must first be attached to the RPD machine gun.
  2. The operator must then inspect the belt loading tab to ensure that it is protruding from the trap door of the drum.
  3. The operator will then need to pull downward on the drum’s lock, which is located on the bottom of the receiver.
  4. The operating handle needs to be pulled toward the rear, which will cause the RPD machine gun to become cocked. 
  5. The feed tray’s cover latch must then be pushed into the forward position, followed by opening the top cover.
  6. The operator will need to put the belt on top of the feed tray with the first round facing toward the cartridge stop.
  7. The operator will then need to ensure that the cover is closed.

At this point, the RPD machine gun is loaded and ready to be fired. To continue with firing, the operator may apply the safety catch, located to the right of the pistol grip. If the safety is in the forward position, the trigger cannot be fired.

As such, the safety catch needs to be applied to the rear position. Once actuated, the operator may commence with firing. When the RPD machine gun is ready to be unloaded, the feed tray will need to be pushed forward and the cover lifted. Finally, simply remove the belt from the gun and close the cover. 

Now that you understand the basics of firing the RPD gun, let’s talk about its disassembly and what steps need to be taken to complete its teardown.

Disassembly – Breaking Down the RPD Machine Gun

  1. If you wish to disassemble the RPD, begin by removing the belt and making sure that the weapon is safely cleared.
  2. By pulling the trigger, you will cause the slide to move forward and under control.
  3. Then, push the locking latch forward on the spring-loaded top cover. This will allow you to lift up on the receiver cover. 
  4. Now, you will need to remove the cover. To do this, you will have to move the pivot pin out and to the right.
  5. You are now ready to turn the butt trap cover over. This is to the right angle of the butt.
  6. Using a screwdriver, make sure to turn the recoil spring, as well as the buffer plug assembly to the “ON” position. To do this, simply employ a quarter turn either to the right or left.
  7. You may now remove the buffer assembly, the recoil spring, and the guide rod.
  8. After pushing the buttstock’s retaining pin, you will be able to remove the pistol grip, the slide assembly, and the buttstock.
  9. Pulling the operating handle to the rear position will let you remove it.
  10. Follow this by removing the slide assembly.
  11. Finally, remove both the bolt and locking lugs from the slide.

A Word on the Gas Regulator

The RPD is equipped with an adjustable gas cylinder. However, the gas block and its cylinder are affixed to the barrel. The gas block consists of a regulator that has three variable positions.

If you look closely, you will notice that there is an index pin that is labeled “1, 2, 3.” Perusing the Soviet Union’s Army operating manual, you will see that the first position refers to standard use.

If an operator is using the RPD in field operation, setting #2 is going to be more suitable. To make adjustments to the gas regulator, there is a retaining nut located on the left side that needs to be loosed or tightened. 

However, you will need a takedown tool to complete this action. The takedown tool is fortunately located within the buttstock’s maintenance kit. It was very prudent for operators to make doubly sure that nothing happened to the takedown kit during their travels. This could prove to be especially challenging in the heat of battle.

To disengage the index pin for making adjustments, the regulator will need to be pressed down and to the right. It’s important to note that as easy as it sounds, this is one truly heinous task to complete. 

If an operator was using the RPD in the field and had to complete this task, it would likely be nearly impossible. When you factor in how hot and dirty the RPD machine gun would have been, there was little that the operator could do under such conditions.

And if combat was taking place around you, forget about it. And as we discussed, if you happened to lose or misplace the takedown tool, then you would really be up a creek, as you would have no way to make the necessary adjustments to the gas regulator.

Final Thoughts

As you can see, the RPD’s age and history make it a complicated weapon to wield in the modern era. But that’s not to say that it isn’t a worthy weapon. For many collectors, it is an important piece of history, and an exciting weapon to fire! If you are one of these collectors who either owns or wants to own an RPD machine gun, we highly recommend establishing an NFA gun trust to ensure you and others you want to use the weapon are safe to do so from a legal perspective. 

Back in its prime, the RPD machine gun was hailed as one of the most respected weapons on the battlefield, not just for what it could do, but for its advanced construction when compared to many other weapons. 

Degtyaryov certainly had a knack for weaponry and understood the importance of innovating. As such, the RPD machine gun will forever go down in history as one of the most famous guns to come out of the Vietnam era.