On May 10, Sweden’s military announced it would be purchasing a new kind of ammunition for a weapon it already owns: the Carl Gustaf Recoilless Rifle. Although it has a superficial resemblance with the US’s anti-tank gun, the Carl Gustaf Recoilless Rifle is a hollow tube for large-caliber explosives. The barrel of the Carl Gustaf has spiral grooves to improve the accuracy of the rounds. Recoilless rifles are larger than typical rifles and can fire explosives up to ten times the size of bullets. Recoilless rifles have an open back like bazookas. This allows exhaust from the explosive to flow backwards. Shots can then be fired without producing recoil.
Made by Swedish defense giant Saab, the Carl Gustaf is a venerable weapon, a sophisticated and durable rifled tube that first entered military service in 1948. With this latest type of ammunition, called High Explosive (HE) 448, the rifle can pull off a new trick: It can automatically program the round with information from the rifle’s fire control software, promising faster, more accurate firepower on the move. This means that the ammunition and weapon can communicate with each other while the round is being loaded.
The Carl Gustaf M4 combines its rifled tube and sophisticated set of sensors, computers and explosive ammunition. Weighing roughly 15 pounds and stretching about 3 feet in length, the body of the weapon has been shortened and lightened from previous versions. On the weapon, the Fire Control Device, FCD 558, includes sensors for temperature and air pressure, which help it calibrate how the round will travel through the air in the exact atmospheric conditions at the moment of firing.
“The gunner can choose direct fire or air burst using a toggle on his FCD. This information is electronically communicated with the fuze in the round before firing,” states a Saab release . The weapon also features a short video. The gunner uses the same toggle for entering the target’s range. The FCD’s ballistic computing computer calculates the best trajectory for success .”
. It has information about the range, propellant temperature, and required mode.
This allows the shooter to determine whether an airburst, or direct impact, is the best way to attack a target. The weapon will trust that weapon to provide as much information as possible. With an airburst, the HE 448 detonates above or near a target, letting the fragments and blast travel through the air above a group of enemies, a machine gun nest, or even next to the light armor on the side of a vehicle.
“The HE 448 round provides the FCD 558 with the exact information on round type and propellant temperature and combines this with target distance entered by the operator to determine the best trajectory. This means that Carl-Gustaf operators will be able to quickly configure a chambered round and so increase their operational effectiveness,” said Saab in an announcement of the order.
While firing directly at vehicles within range is the easiest way to use the weapon, it’s not always the best option. Programmability is key. Programming an air burst from high explosive rounds above enemy positions will kill enemies if they are within range. This is where fire control, range finding and mode selection are most important.
High explosives are one type of ammunition that can fire with the weapon. A 2017 brochure for the weapon lists 10 rounds available at the time, divided by function. Anti-personnel round that produces smokescreens or blinding lights, anti-armor rounds, and versatile rounds or anti-building rounds are all included. The HE 448 is designed as a specific replacement for the HE 441 RS, an anti-personnel round, designed to incapacitate and kill people caught in its blast.
This makes the weapon useful for ambushing transport vehicles, as well as soldiers fighting in open terrain, hiding behind cover, or nestled into foxholes. The Carl Gustaf, with the HE 448, has a range of over 4,200 feet, or at least 4/5ths of a mile.
At the same time in the 1940s that Saab first developed the Carl Gustaf, the United States was experimenting with a range of larger recoilless rifles for its own forces. In 1945, Popular Science covered the 57-MM as a “Kickless Cannon for GI’s.” The 57-mm is a large two-person anti-tank weapon that “can be fired as accurately as the [M1] Garand” standard infantry rifle, hurling a 2. 75 pound shell 2.5 miles. A 75-mm version was developed around the same time, with a 90-mm version fielded by 1960.
Some recoilless rifles saw use in World War II, with the Carl Gustaf first introduced into service in 1948. By the Korean War, recoilless rifles became a