Black Storm Defender – Standalone GP-25 Grenade Launcher Stock

In an earlier video we looked at the Black Storm series of bullpup conversion kits for AK pattern rifles. Black Storm have also developed an interesting standalone stock for the GP-25 under barrel grenade launcher called ‘Defender’. The impetus for this is s aid to be that the Black Storm rifle kits aren’t able to support the grenade launchers so a standalone stock into which they can be mounted was developed.

The GP-25 is a 40mm grenade launcher designed in the late 1970s by the small arms design bureau based at Tula. It is an under-barrel grenade launcher designed to slide onto standard issued AK-74 pattern rifles. Its ammunition uses a high–low pressure system and has a range of up to 400m.

The most interesting feature of the GP-25 stock is that it has a recoil mitigation system. This appears to be a strong spring in the telescoping stock tube which acts as a buffer. The stock kit is made up of a telescoping stock with butt pad, onto which the grenade launcher is mounted – just as you would onto a rifle, a forward vertical grip can be attached by a clamshell pair of metal stampings with allow the grip piece to be centered and held in place by two cross nuts. There is also a press-fit pistol grip extension for the GP-25’s short grip to help improve ergonomics.

Black Storm list the stock kit without launcher as weighing 200g while the Defender with GP-25 is listed as weighing 500g (1.1lbs). Black Storm sell the V2.0 of the stock for 5,950 UAH ($162).

*A GP-25 in a Black Storm Defender stock (via War_Noir)*

With some units also transitioning to NATO calibre rifles like the M4A1, MSBS GROT, FN FNC and F2000 amongst others, the ability to use the GP-25 as a stand alone weapon has proven valuable as the GP-25 can’t be mounted on Western rifles but with ammunition for the grenade launchers still plentiful they can continue to be used.

The earliest imagery I could find of the Defender in the field dates to 22 April, when Russian reporter War Gonzo posted a short video showing a Defender captured by Separatist DPR troops in Mariupol. The DPR soldier examining it notes that the weapon doesn’t seem to work and also compared it to the GP-25 fitted to his own AKS-74.

In May a good, clear photograph of a GP-25 in a Defender stock was shared, shown fitted with a sling. In mid-May Ukrainian operators shared a video of the Defender being fired at the range.

Also in May a short video of a Defender kit being fitted to a launcher was shared – this particular example apparently requiring some hand fitting to the sheet-metal pieces that attach the forward grip.

A number of other stand alone adapters for GP-25s have also been seen in the field, In late May 2022, this example of a simpler adapter was shared online featuring a rigid stock onto which the grande launcher can be fitted. Simple adapters like this may be craft made in the field or manufactured by commercial companies.

*A GP-25 in a Defender stock (via social media)*

In June a short video was shared of a Ukrainian soldier firing several high-angle rounds from a GP-25 mounted in a Defender stock, we can see that the sight has been set to its highest elevation.

Ukrainian operators shared another photograph of a GP-25 in a Defender stock in September. The North Side Group shared a photograph of a GP-25 in a Defender at what appears to be a range in mid-September.

Russian operator shared photo of two standalone stocks for the GP-25 – the first is the rigid stock type seen in the photo from May. I haven’t been able to ascertain who produces this stock yet. In these photos, however, it is clear that the butt is wider than the Ukrainian design. The second stock appears to be a Black Storm Defender [Update: since identified as a RGL Север 1].

On 30 November the Belarusian volunteer unit, the Kalinouski Regiment, shared a video demonstrating the Defender, showing how its loaded, fired and carried noting that it is “designed to destroy enemy manpower located in trenches, and open terrain.”

In early January, Assistance Group – a German group active in Ukraine, shared some photographs of load out for operating in urban and woodland environments and a GP-25 in a Defender feature in both photographs.

At the beginning of February 2023 a video was shared featuring an operator with Russia’s SOBR “Granit”, he fires a couple of rounds from a GP-25 in a stand alone stock [Update: since identified as a RGL Север 1].

The ‘Lubart’ Ukrainian special operations forces unit recently shared a number of montage video of operations around Bakhmut. In it one operator loads and fires a Defender several times. The Defender in the clip lacks the pistol grip extension that comes as part of the kit.

*A GP-25 Defender and a pair of customised AKs (via social media)*

On 2 March a member of the Forward Observations Group shared a photo of is various weapons including a Black Storm Defender.

Finally, most recently, a short video from a Russian anti-Putin group – the Russian Volunteer Corps, filmed during an apparent raid into Bryansk. The video featured one of the group’s leaders with a Defender slung at his side.

It’s unclear just how many of these Black Storm Defender stock kits are being used by Ukrainian personnel but they do continue to appear regularly in imagery from the field. While unsurprisingly they appear to be favoured by units armed with Western rifles they are also being used by combatants armed with weapons which could mount a GP-25, perhaps indicating a preference for using the launcher as a stand alone weapon.

Update 30/04/22 – Russia’s RGL Север 1

Since writing the article further research has discovered a very similar stock design originating from Russia. Developed by a company called RGL (redgreenlight.ru). RGL have developed a number of products including a sight mount for RPG/RPO pattern shoulder-fired launchers and a small light which can illuminate turrets on optics for use in lowlight conditions. They developed their stock for the GP25 and GP34 in 2019, with refinements in 2022. It was reportedly developed independently of the Black Storm Defender – with both companies developing very similar products.

RGL’s website has some specs on their system – the Север 1, noting its length is 480mm and its weight is ‘no more 1100g’. The stock adapter is priced at 17,000 Russian Ruble (or around $220).

*Photos of the Север 1 with GP-25 fitted and disassembled (via RGL)*

So similar are the two designs that images at 5:21 and a clip at 6:55 actually show Север 1s rather than Defenders. A Wagner-affiliated Telegram channel posted the photo below, with the caption: “For those who want to order – mid-May production time, place an order in advance.”

*An RGL Север 1 fitted with a TAG-35, an airsoft clone of the GP-34 grenade launcher (via social media)*

The key differences between the two appear to be a different kind of butt pad, the positioning of the sling loops, some machining on the extension which attaches to the launcher and most fundamentally a reversal of which parts of the stock telescope. On the Defender the rear section telescopes inside the front while on the Север the front portion appears to telescope inside the rear section. The Север 1 does not appear to come with a frontgrip or a grip extension. The Север 1 has been seen in use in Ukraine with Russian combatants.

Support Us: If you enjoyed this video and article please consider supporting our work here. We have some great perks available for Patreon Supporters – including early access to custom stickers and early access to videos! Thank you for your support!

Bibliography:

Black Storm Defender, Black Storm, (source)

Video demonstrating assembly of Defender, Black Storm, (source)

Thanks to the guys at Streaking Delilah, War_Noir and to Abraxas Spa for their help with imagery for this video.

Diemaco/Colt Canada M203A1

The Diemaco M203A1 is a development of the M203 40x46mm low velocity grenade launcher. The M203 was initially developed by AAI to replace the Colt XM148 which proved overly complex when tested in Vietnam.

The Diemaco M203A1 improves on the earlier launcher by incorporating its sight into the mount rather than being atached to the top of the barrel. The Diemaco M203A1 should not be confused with the Colt-manufactured M203A1 in US service. The Diemaco launcher is offered alongside the C7 and C8 rifles made by Diemaco (now Colt Canada).

SEAL members emerge from the water during tactical warfare training c.1986. The SEAL member in the foreground is armed with an M-16A1 rifle equipped with an M203 grenade launcher (US National Archive)

Diemaco developed the M203A1 so it has a longer action, with the breech opening further to allow the firing of all 40×46 mm LV grenades including less than lethal baton rounds. It can also be mounted on all AR-patterned rifles as well as the Steyr AUG.

Like the original M203 the launcher can be operated by either a left or right handed users. The original model had an iron sight assembly has dual azimuth adjustment knobs and an elevation dial, this model, however, has a simplified tangent sight. Diemaco stated that the M203A1 has a maximum effective range of 400m (440 yd) with a muzzle velocity of 78 m/s (260 ft/s).

diemaco M203a1 brochure — Diemaco brochure cover showing M203A1 on a C7 rifle (Colt Canada)

The M203A1 was tested by the UK’s special forces in the late 1990s, when they evaluated the Diemaco SFW carbine, which was subsequently adopted as the L119A1. The Heckler & Koch M320 GLM (HK AG36) has since been adopted by the British Army.

If you enjoyed the video and this article please consider supporting our work here. We have some great perks available for Patreon Supporters. You can also support us via one-time donations here.

Specifications (From Diemaco Brochure):

Calibre: 40 mm
Loaded Weight: 2.15 kg (4.74 lb)
Empty Weight: 1.85 kg (4.08 lb)
Overall Length: 318 mm (12.52 in.)
Barrel Length: 228.6 mm (9 in.)
Overall Height: 140 mm (5.51 in.)
Rifling: Right Hand Twist – 6 Lands
Rate of Twist: 1 turn in 48 in. (121.9 cm)

Bibliography:

Diemaco M203A1 Product Brochure, Diemaco/Colt Canada, c.2000

Diemaco M203A1 for SFW carbine, Royal Armouries, (source)

Colt CGL-4 (XM148) 40mm Grenade Launcher

Here’s Vic’s video on the XM148, check out Matt’s article below:

There have been attempts to fire grenades from the infantryman’s weapon since the 17th century. Up until the 1960s these almost entirely involved muzzle attachments or grenades which could be fired off the end of a rifle’s barrel. In May 1963, the US military called for a new ‘underslung’ grenade launcher to complement the AR-15/M16, then in early testing. The grenade launcher program had its roots in the ultimately unsuccessful Special Purpose Individual Weapon (SPIW) program which had begun in 1952.

While a series of designs were developed by various manufacturers and designers, May 1964 saw Colt unveil the CGL-4. The Colt was tested against designs from Springfield Armory and Ford, a design from AAI was promising but it was not able to chamber the 40x46mm rounds used by the M79 and was rejected. The US military sought munitions commonality between the M79, already in service, and the new rifle-mounted grenade launcher.

DCC CGL-4 NO SOUND_Moment2 — Left side view of the XM148’s bulky tangent sight (Vic Tuff)

In March 1965, the CGL-4 was chosen for further testing and a contract for 30 launchers was signed. The CGL-4 was reportedly developed by Karl Lewis and Robert E. Roy in just 48 days. However, the design was complex. To load the barrel housing slid forward allowing a grenade to be placed in the breech, the weapon was then cocked and a long trigger, which projected back towards the rifle’s trigger guard, could be pulled to fire the weapon.

CGL4 Patent — Karl Lewis & Robert E. Roy’s patent for the Colt CGL-4 (US Patent Office)

Despite some problems with barrel housings cracking an order for 10,500 of the new launchers, now designated the XM148, was placed in January 1966. Production capacity issues and problems with the launcher’s sight lead to production delays and it wasn’t until December 1966, that the first shipment of 1,764 launchers arrived in Vietnam for field testing.

DCC CGL-4 NO SOUND_Moment6 — Right side view of the XM148’s trigger, cocking mechanism and pistol grip (Vic Tuff)

Initial reports from the field were promising with troops praising the “tactical advantage of both the point fire and area fire system” concept. The XM148 was well received by the SEALs and the Australian SAS. The armourers of the Australian SAS, deployed to Vietnam with the 1st Australian Task Force, were also hard at work attaching XM148s to L1A1 rifles. Removing the L1A1′s handguard and attaching the XM148 to the rifle’s barrel.

Field testing was carried out by 12 units from six different divisions which were operating in various parts of Vietnam. This gave a wide variety of terrains and yielded some interesting results. In general it was found that the XM148 decreased rate and quantity of the grenadier’s fire, it slowed his reaction times when firing at a target, it hampered his movement in dense vegetation and also meant the grenadier had to spend longer caring for his weapon.

DCC CGL-4 NO SOUND_Moment4 — XM148 with breech open (Vic Tuff)

It was noted that the sight mount which was overly complex and prone to snagging on brush and kit, it was also felt that too much force was needed to cock the XM148 (around 30 lbs) and the trigger mechanism was felt to be overly complex and difficult to repair and disassemble. One safety concern was the XM148′s long trigger bar, which could snag and launch a round – not ideal for special forces patrols infiltrating through thick bush. Problems with the launcher’s quadrant sights also continued causing deflection errors out at longer ranges. The bulkiness of the sights exasperated these problems as when they were knocked the XM148′s zero could be effected. The XM148 also precluded the use of a bayonet as when fired it would blow the bayonet off the muzzle. Overall, troops felt the XM148 was too fragile and complex for use in the field.

XM148 in vietnam — SP4 Willey firing an M16A1 mounted with a Colt XM148 c. 1967 (US National Archives)

At least one unit found use for the launchers, the 1st Cavalry Division (Airmobile)’s Operational Report for Quarterly Period Ending 31 October 1967, noted that the XM148

“proved unsatisfactory in infantry units due to its lack of durability; consequently, USARV directed that they be turned in. However, 1/9 Cav has devised a method of mounting the launcher coaxially on the M60C machine gun used by scout observers on OH-13 scout helicopters. Durability in this environment is
not a problem since the weapon deos not receive the rough handling it did in the hands of ground troops. Firepower on scout helicopters is significantly increased. Fifty-two XM148s have been retained for use by 1/9 CAV.”

Finally, despite Colt’s efforts to rectify the growing list of problems the Army Concept Team In Vietnam deemed the XM148 unsatisfactory for deployment in Vietnam and recommended they be removed from service and a new improved launcher be developed. This was a massive blow to Colt who had already manufactured 27,400 XM148s. Many of these were already in Vietnam.

The US Army launched the Grenade Launcher Attachment Development (GLAD) program in the summer of 1967. A large number of manufacturers submitted designs including Colt, who offered the improved Henry Into-designed CGL-5. The Army turned down Colt’s offer of 20 free improved launchers and rejected the CGL-5 outright. The GLAD program saw the resurgence of the earlier AAI design, designated the XM203, this simple design, now chambering the 40x46mm shell, was eventually selected in August 1968. Ironically, as AAI was predominantly a research and development company and after an initial run of 10,000 made by AAI, Colt was subsequently awarded the contract to manufacture the M203 from 1971 onwards.

Harold Into’s patent for the product improved CGL-5 (US Patent Office)

While the XM148 proved to be a failure it played an important role in proving the operational viability of the rifle mounted grenade launcher system. The muzzle-launched rifle grenade is all but obsolete, superseded by the under-slung grenade launcher.

If you enjoyed the video and this article please consider supporting our work here.

Specifications:

Length: 16.5 inches
Weight: ~3lbs
Calibre: 40x46mm
Action: single shot, striker-fired single action
Capacity: 1
Rate of Fire: ~4 rpm

Bibliography

Images: 1 2 3 4 5 6

Black Rifle, E.C. Ezell & R. Blake Stevens, (1987)

Colt Industries Newsletter, Vol.2 no.3, May 1967, (source)

‘Grenade launcher having a rotatable forwardly sliding barrel and removable firing mechanism’, US Patent #3507067, H.A. Into, 14/12/67 (source)

Operational Report for Quarterly Period Ending 31 October 1967, 1st Cavalry Division (Airmobile), (source)

‘Grenade launcher’, US Patent #3279114, K. Lewis & R. Roy, 25/09/64 (source)

Springfield Armory Database entries: 1 2 3

40mm Shoulder-Fired Grenade Launchers & the SEALS, Small Arms Review, K. Dockery, (source)

The XM148: Birth of the Mounted 40mm Grenade Launcher, Small Arms Review, J. Wong, (source)

My thanks to Daniel Watters for information on AAI & Colt M203 production contracts.