July 10, 2020: For the first time since the 1950s a new self-propelled anti-aircraft system has been developed using a 57mm gun. In development for over five years Russia recently showed off the finished product, the 20 ton self-propelled 2S38 Derivatsiya-PVO, a single barrel 57mm autocannon that can fire 120 rounds a minute although that capability is only used in short (2-4 round) bursts of aimed fire, usually with guided or programmed (to explode at a certain location) shells. The 2S38 vehicle is based on the BMP-3 IFV (Infantry Fighting Vehicle). The BMP-3 manned turret is replaced with what amounts to a 57mm RWS (Remote Weapons System). The three-man crew (driver, commander and gunner) operate inside the vehicle, which carries 80 rounds of 57mm ammo for the autoloading long (8.5 meter) barrel 57mm gun guided by a passive (optical/thermal) sight to detect targets. That means aircraft with radar detectors will not know the 2S38 is down there, ready to open fire with radar-equipped or laser-guided shells that are effective up to 8,000 meters.

The radar fuze was a late World War II development that crippled the effectiveness of the Japanese Kamikaze (suicide pilot) attacks against American carriers and other warships. The many 5 inch (127mm) rapid-firing guns on these ships, using the radar proximity shells only had to fire in the general direction of the incoming Kamikaze aircraft. The radar fuze would detonate the shell when it was closest to the target. This created a wall of very accurately placed shell fragments that shredded incoming swarms of Kamikazes. The U.S. Navy didn’t expect the Kamikaze, but the Japanese didn’t expect the radar fuze or long-range aircraft detection radar on ships and some larger carrier aircraft. These technical surprises doomed Japanese hopes for gaining a military edge with their suicide pilot program.

The 2S38 was designed to use technology to obtain a similar element of surprise against contemporary enemy helicopters and UAVs. The usual countermeasures (radar and incoming missile detectors) won’t work while the 57mm shell is much faster than any missile and a lot more difficult to jam. The 2S38 not only fires laser-guided and radar fuze shells, but also shells programmed to detonate at a certain point in flight. These are the old VT (variable time) fuzes updated to work with a fire control system which plot the probable course of a helicopter or UAV target and program several shells to detonate as they arrive at where the targets are expected to be in the next few seconds.

The 2S38 can also use high-explosive (for bunkers or buildings to support ground attacks) or armor-piercing (to destroy light armor and cripple tanks) shells. Vehicles up t0 3,000 meters distant are vulnerable. High explosive shells are accurate out to 4,000 meters. Not all the smart shells have completed development but Russia has already mastered most of the remaining tech the 2S38 depends on. If they can get everything 2S38-related working together reliably, they will have a breakthrough weapon firing a wide variety of two kg (4.4 pound) shells.

Meanwhile many nations still use older tech self-propelled anti-aircraft guns. Since the 1950s self-propelled anti-aircraft gun systems used more modern, smaller caliber and faster firing autocannon. Most current models use 35mm guns and the Swiss Oerlikon 35mm is the most widely used via manufacturing licensing agreements with many countries.

China is a big fan of these 35mm anti-aircraft gun systems. In 2013 China revealed a wheeled 8x8 anti-aircraft system equipped with a radar and a single 35mm autocannon. This was very similar to an earlier tracked version that contains the same radar and two 35mm autocannon. In both cases, the gun appears to be a licensed copy of the Oerlikon 35mm. The tracked version weighs 34 tons while the wheeled version weighs about 10 tons less and moves more quickly on roads and requires less maintenance.

The 35mm gun is a popular weapon for armored, self-propelled anti-aircraft artillery. Systems of this type were first developed in Europe. These fire 2.5 kg (5.5 pound) rounds at the rate of 300 a minute. Max altitude is about 4,000 meters (13,000 feet). The 35mm projectiles weigh up to .75 kg (1.65 pounds). This AAA (Anti-Aircraft Artillery) is still useful against helicopters and transports and jets that are moving slowly over the battlefield.

Meanwhile Russia continues to manufacture and sell its 30mm Tunguska M1 self-propelled anti-aircraft system. This weapon first appeared in the 1990s and India was one of the first customers, buying 24 vehicles at a cost of about $17 million each (including spares, maintenance support and extra missiles). That's enough for four batteries. Germany, Peru, Ukraine and Morocco have also bought the system. India had already bought 60 of the older (1986) model of the Tunguska. The current version of the Tunguska entered service in 1998, and over 300 of both versions have been manufactured so far.

The 34-ton Tunguska vehicle carried carries radar, two 30mm cannon (with 1,936 rounds of ammo) and eight 9M311 (SA-19) missiles (plus up to four missiles for reloads). The missiles have a ten-kilometer range against air targets and six kilometers against ground targets. The missile can hit targets at up to 8,100 meters (26,000 feet). The 30mm cannon is effective up to 3,000 meters (9,6000 feet), and can hit ground targets 4,000 meters away. The vehicle has a crew of three. The fire control system can use line-of-sight as well as radar, guidance. The new version makes it easier to use the missiles, or guns, against ground targets. The 40 kg (88 pound) missile (also called Tnnguska,or 9m311) has a 9 kg (20 pound) warhead, and a lot of velocity when hitting something. As a bunker buster, it would be useful. The Russians have also noted that, since World War II, few of these self-propelled anti-aircraft weapons get an opportunity to shoot at something in the air, but there are always plenty of ground targets.