Russo-Ukrainian War: The Zastava M55 20mm Automatic Cannon

Source: Ministry of Defense of Ukraine

     A soldier belonging to the 243rd. Territorial Defense Battalion, 241st. Territorial Defense Brigade sits in the gunner's seat of a Zastava M55 20mm automatic cannon. The photograph was taken in the winter of 2023. The M55 is a Yugoslavian (now Serbian) license built Hispano-Suiza HS.804 20mm L/70 anti-aircraft cannon mounted on a Hispano-Suiza HS.630-3 towed carriage. Originally built by the Crvena Zastava arms company (now Zastava Arms), the single-barrel M55 (some sources designate it the 20/1 mm M55) first entered service with the Yugoslav People's Army in 1955. Despite the age of the M55, it remains in production as it is robust and dependable. Slovenia provided Ukraine with 200 M55 systems, both single-barrel and triple-barrel (known in some sources as the 20/3 mm M55), in 2022.

     The M55 is chambered for the 20x110mm HS round and it has a gas operated, delayed blowback action. The M55, sans the carriage, has an empty weight of 94 pounds and with a full 60-round drum magazine, the weight increases to 151 pounds. The maximum rate of fire is between 600 to 700 rounds per minute with each round leaving the barrel at a muzzle velocity of 2,800 to 2,900 feet per second. With the muzzle brake, the recoil force is 881 pounds.

     The 20x110mm HS cartridge case was brass with more modern production ammunition using steel cases. The standard HEI (High-Explosive Incendiary) round has approximately 32 grams of propellant with between 10.75 to 11.4 grams of explosive. The effective range against aerial targets is just under 1 mile (.9 of a mile) while the maximum range of the round is 2.7 miles. Fuzes include delayed-action and impact types. The M55 shown here is not fitted with any sights but the mount for an optical sight can be seen above the magazine.

     The M55 can fire against ground targets if need be with an effective range of 1.2 miles. Today, the typical ammunition availability for the 20x110mm HS round (in addition to the HEI discussed above) includes HEI-T (High-Explosive Incendiary Tracer), HE-T (High-Explosive Tracer), and HE (High-Explosive). Armor-Piercing (AP) ammunition was made for the cannon but performance required the M55 to be at close range to be effective. The AP round could penetrate 15mm of hardened steel at a 40 degree slope at a range of 365 meters. A more effective APCR (Armor-Piercing Composite Rigid) round, using a tungsten core, was produced that allowed for around 38mm of armor penetration at 365 meters at a 30 degree slope.

     As the M55 is manually operated, the cannon is mainly in service with anti-UAV units as the slow speed of drones such as the HESA Shahed 136 (around 115 miles per hour) are more easily tracked and targeted by such weapons.

Russo-Ukrainian War: Supacat HMT 600 w/ ASRAAM

Source: Ministry of Defense of Ukraine

     In February 2024, a video appeared online showing this vehicle, a British Supacat manufactured 6x6 HMT 600 (High Mobility Transporter) which is fitted with a launch system for the British ASRAAM (Advanced Short Range Air-to-Air Missile; AIM-132 in U.S. service) short range missile. It was originally believed this was the British Gravehawk SAM system but more recent reports state the pictured “FrankenSAM” is not Gravehawk. The final Gravehawk system is fitted within a standard shipping container which is transported by a Leyland DAF 8x8 DROPS (Demountable Rack Offload and Pickup System) truck. It uses Soviet-era Vympel R-73 missiles that are utilized by Ukrainian Air Force fighters as short range AAMs (Air-to-Air Missiles). As there is a surplus of R-73 missiles (NATO reporting name AA-11 Archer) due to the fact air-to-air combat between Ukrainian and Russian jets is rare, the R-73 is seeing use as a SAM.

     However, the launcher on the Supacat HMT 600 is very similar to the one used on the Gravehawk, down to the shiny bolts that hold it together. In addition, the mast mounted sight is nearly identical to the one used on the Gravehawk. So, it is very possible that some of the equipment and apparatus seen here on the Supacat HMT 600 was incorporated into the final Gravehawk system.

     Returning to the ASRAAM, it entered service in 1998 and it uses a dual-burn, high-impulse solid fuel rocket motor that can accelerate the ASRAAM to speeds exceeding Mach 3 (2,300 miles per hour). The maximum range around 30 miles. For a warhead, the ASRAAM has a 22 pound HE-FRAG (High-Explosive Fragmentation) payload and it can be triggered by one of two means: proximity fuze or impact. The ASRAAM uses LOAL (Lock-On After Launch) which means it can be launched and the onboard inertial guidance system will guide the missile towards the target, making adjustments as necessary to ensure a hit. There looks to be a Chess Dynamics Hawkeye optical suite which provides targeting, tracking, and target identification for the operator. The suite can be used with the ASRAAM to bring it to bear on a target. Speaking of targets, the ASRAAM is primarily deployed against Russian drones, loitering munitions, and cruise missiles.

     As for the HMT 600, it is powered by a Cummins 6-cylinder diesel engine developing 180 horsepower and this provides for a top road speed of 75 miles per hour. The engine is paired to a Allison 5-speed automatic transmission. 53 gallons of fuel provide for a maximum cruise range of 435 miles. The cab is armored though to what level isn't stated in Supacat literature. It is also mine-resistant, in part due to the high wheelbase. Other features include ABS (Anti-lock Brake System), power steering, adjustable ride height, and four-wheel drive. As optional items, the HMT 600 can be fitted with runflat tires, self recovery winch, smoke grenade launchers, a RWS (Remote Weapons Station) mount, and IR lights.

Russo-Ukrainian War: The KS-19 100mm Anti-Aircraft Gun

Source: Reddit

     Another venerable artillery piece is shown here, the KS-19 100mm anti-aircraft gun. First accepted into service in 1948, the KS-19 was the long range companion to the AZP S-60 57mm anti-aircraft gun, the latter engaging targets at short- to medium ranges. In fact, both weapons shared the same SON-9 (NATO reporting name Fire Can) fire director radar while in Soviet service. The advent of SAMs (Surface-to Air Missiles) saw the KS-19 phased out with no attempt to keep it viable with modern target detection and fire control systems as has been done with the AZP S-60. Thus, the Soviets sold off most of the approximately 10,500 KS-19 to friendly client states and the gun still sees service to this day with a little over a dozen countries. The KS-19 first appeared in the Russo-Ukrainian War soon after the start of the conflict when the Russians captured a number of Ukrainian KS-19 guns that had been in storage in the city of Balakliia, Kharkiv Oblast. Lacking ammunition, the Russians set up some of the KS-19s as decoys. The Ukrainians retook the city on September 10, 2022 during the Kharkiv counteroffensive and recovered the KS-19 guns. In the spring of 2023, the KS-19 next appeared in Ukrainian service as ammunition had been acquired (or located from stocks). Since then, the KS-19 has shown up in social media from time to time with some of the guns mounted on heavy trucks. The KS-19 is deployed as a quick firing artillery gun, delivering indirect fire (or even direct fire) against enemy targets.

     The towed KS-19 weighs in at 10 tons and so once it is set up in a firing position, it cannot be manhandled around. In Soviet service, the KS-19 was usually towed by a fully tracked AT-S or AT-T prime mover but any truck with a compatible towing ability can be used as well. Maximum tow speed on roads is 25 miles per hour. It takes time to both set up the KS-19 as well as prepare it for moving which makes it vulnerable to counter-battery fire. This is one reason gun trucks using the KS-19 have been put into service to provide more rapid mobility. The gun uses a semi-automatic, horizontal sliding wedge breech block which means that after firing, the empty shell case is automatically ejected from the breech. The KS-19 has a power rammer and a well trained crew (a full crew is 15 men though as few as 7 men can man the KS-19) can manage a maximum of 15 rounds in a single minute. A more sustained rate of fire is 9 rounds per minute while a hour long bombardment is between 1 to 2 rounds per minute. This allows for barrel cooling. The KS-19's gun mount permits a maximum elevation of 85 degrees and no more than 3 degrees of depression. The mount sits on a turntable which permits 360 degrees of traverse. While moving the gun is manual, the traverse and elevation controls are powered. 

     The photograph here shows a KS-19 in a dug-in position and it has a rather worn looking appearance. The two seats are for the gunners who control the gun's position. The dual hand cranks are for the traverse while the single hand crank is for elevating and depressing the gun barrel. The squarish box-shaped components contain dials which contain the azimuth and elevation indicators and for the one at the rear, the fuze setting apparatus (which would be used if the KS-19 was engaged in anti-aircraft fire). The telescopic sight for direct fire is visible along with the corresponding round aperture in the gun shield. Right behind it is the panoramic periscope sight used for indirect fire. The top half of the gun shield can be lowered down with the shield thick enough to only provide protection against light small arms calibers and shell splinters.

     When firing the UOF-412 HE (High-Explosive) round, the KS-19 can lob the shell and its 3 pound TNT warhead out to a maximum of 12 miles. The shell uses a V-429 series fuze and a NDT3 propelling charge. If forced to combat enemy armor, the KS-19 can fire the BR-412B AP-T (Armor-Piercing Tracer) round that has a maximum range of 2.5 miles but an effective range of .6 of a mile where the BR-412B can penetrate up to 185mm of armor. The BR-412B uses A-IX-2 explosive and also utilizes the NDT3 propelling charge.

     It is not known exactly how many KS-19 are in active service with Ukrainian forces but as of March 17, 2025, none have been reported as lost by the Oryx website.