A YouTube channel called WarDoc has published a video where they show a rifle grenade launcher made in self-proclaimed Donetsk People’s Republic. This device is basically a tube attached to the muzzle of an AK-74 rifle. Instead of purpose made rifle grenades, it uses the projectiles of 23x152mmB autocannon rounds. As in the case of many other rifle grenades, in order to shoot it, one must load a blank cartridge into the rifle, load the grenade (the 23mm projectile) from the muzzle and shoot the gun. Let’s watch that video then discuss some design aspects of this launcher:

Design of the Launcher

In the video, they say that they are using a blank cartridge with an increased powder charge. The reason for using more powder can be the need to increase the distance of shell’s flight. However, it may also be necessary to have enough muzzle velocity to activate the time fuze.

Judging by what blank cartridge they show in the video, I suspect that they just remove the bullets from normal 5.45x39mm rounds, completely fill the case with powder and seal it. It can also be one of the blank  5.45x39mm cartridges with the white plastic bullet cut at the case mouth.

Note the 5.45x39mm blank cartridges with white plastic bullets

The blank 5.45×39 cartridge they use looks to be made of a normal 5.45x39mm case.

The 23mm shell they use is an HEI projectile with a self-destruction mechanism (time fuze). As you can see in the video, the projectile detonates in the air. I think the use of a time fuze is the key point that makes this system work. Here is why. This launcher is most likely a smoothbore one. Making a rifled tube would require some advanced machinery and it would also require the muzzle-loaded projectile to have pre-cut grooves on the driving band to make it possible to insert it from the muzzle. Such rifled muzzleloading system is utilized in Russian GP-25 and GP-30 under barrel grenade launchers and VOG-25 caseless grenades. The 23mm shells they use are designed to be spin stabilized. That being said, it these were projectiles that detonate only upon impact (with a contact fuze), then the whole improvised system wouldn’t work, because based on the described arguments, I am pretty sure that this launcher just throws the shells without any stabilization whatsoever, with an unpredictable flight pattern and no guarantee of landing nose first. However, if you have a shell that has a time fuze and will detonate after several seconds regardless of its flight pattern, then this becomes kind of a DIY area suppression weapon which should not be too accurate but may still be useful depending on the circumstances.

As you can see, this is a smoothbore launcher

The man in the video says, that when shooting at closer ranges (100 meters) at enemy positions, these shells land somewhere near the target, then after a short time they detonate. According to most of the sources, these fuzes will also detonate the shell upon impact if the impact has happened before the self-destruction time. This confirmes my theory of the shells fired from this launcher being unstabilized. If they were flying straight, then they would detonate upon impact at the mentioned close ranges. So the only reason why this system works is the time fuze.

This launcher also shouldn’t have any retention mechanism for the 23mm projectile. The shooter probably must hold the gun pointed up (at least slightly) to make the gravity keep the projectile in the launcher. It may have a friction based retention but that is barely anything you can rely on and expect consistency from.

Despite the mentioned drawbacks, it is not a bad improvised solution for what it is. It should also be extremely easy and cheap to make. This launcher is basically a tube made of a decent strength metal with an internal diameter matching the groove diameter of the 23mm projectile and with 24×1.5 metric threads to mount on AK-74 rifles.

The ZU-23-2 Anti-Aircraft Autocannon and the 23x152mmB Cartridge

The 23x152mmB cartridge is mainly used in the ZU-23-2 anti-aircraft autocannon. It is a really widespread piece of armament in the post-Soviet countries (including Ukraine) as well as many other countries around the world. This is also a fairly old autocannon (designed in the ’60s) and doesn’t really work well in the anti-aircraft role anymore. In the recent conflicts, you will more often see it in ground fighting roles than trying to take down a modern jet. You might have seen them mounted on vehicles in the conflicts in the Middle East.

ZU-23 twin barrelled autocannon

A pair of ZU-23s

ZU-23s mounted on pickup trucks. Libya, 2011.

Another modern alternative use of the ZU-23s is the use of their barrels to make anti-materiel rifles. Such weapons were several times noticed in the Syrian conflict.

One of the improvised anti-materiel rifles based on a ZU-23 barrel. Syria.

23x152mmB is a belted bottleneck autocannon cartridge. It was loaded with a variety of projectiles including the one discussed in this article.

Cutaway of the 23x152mmB projectile

23x152mmB (top) compared to 25x137mm round used in M242 Bushmaster autocannons

If I was designing this device, I would also add external threads to the front end and make a simple baffle stack that could be dropped into the tube, screwed in place via a front cap and turn the launcher tube into an improvised suppressor. I am talking about something like the PBS-1 baffle stack.

Note the simple baffle stack assembly of the PBS-1 suppressor

Although it would have a very small internal volume, it would still suppress the sound to some level and could at least make it harder to detect the shooter. That way, one could have a multi-purpose device.

Sources:

WarDoc. (2018, February 15). ЭКСКЛЮЗИВ! Как автомат превратить в ЗУ-23? Ноу-хау ВПК ДНР [Video File]. Retrieved from: https://www.youtube.com/watch?v=GYK6qyW2EyM

Images from: www.quarryhs.co.uk, www.wikipedia.org, forum.guns.ru, www.gunmag.com.ua, screenshots from the embedded video.