In 1946, Hugo Abramson and Harald Jentzen of the Kungliga Arméförvaltningens Tygavdelning (Royal Swedish Arms Administration) developed the Carl Gustaf M1 recoilless rifle to replace the existing Pansarvärnsgevär m/42 20mm recoilless rifle that had entered service in 1942. The M1 was far larger at 84mm and rather than use fins to stabilize the rounds, the barrel was rifled to impart spin on the round for stabilization. Taken into Swedish military service in 1948, the M1 (designated the 8,4 cm Granatgevär m/48 in Swedish service) enjoyed a longer, more accurate range thanks to more propellant in the ammunition. The only drawback was a low flight speed of the round that limited the effective range against moving targets. Despite this, the M1 enjoyed export sales to a number of countries.
In 1964, the M1 was improved by making the design both lighter and shorter. Designated the Carl Gustaf M2, it rapidly replaced the M1 in Swedish service. It is the M2 that is being utilized in this photograph of two German Bundeswehr gebirgsjäger (mountain troops) training with the weapon sometime in the late 1960s or very early 1970s. Germany was one of the customers of the M2 (under the designation Leuchtbüchse 84mm), purchasing a large number of them to supplement the Panzerfaust 44mm DM2 “Lanze” anti-tank weapon that had entered service in 1963.
The M2 is 3.8 feet long and has a empty weight of 31.3 pounds. It does have a protective carry case for transportation but this adds a further 33.7 pounds to the carry weight. The rifled tube ends in a rear-mounted, up-rotating venturi, seen behind the firer's head. While the M2 could be operated by a single soldier, the M2 is more often served by a two man crew. The loader is making ready the M2's High-Explosive Anti-Tank (HEAT) round which is characterized by the stand-off probe on the front. However, in this case, the ammunition appears to be a inert training round given the wear of the paint on the warhead (from being reused over and over) and that the cartridge case appears to be missing. The firer is provided with a monopod which can be seen just in front of the firer's chin. This monopod can be moved to the front of the tube if desired. For sighting, the M2 uses a simple open sight or, as seen here, a X2 telescopic sight with a 17 degree field of vision. The scope sight does allow for the firer to compensate for environmental temperature which can effect the round. The M2 can be fired from the shoulder, fitted to a vehicle mount, or fired from the prone position which is what we see in the photograph. Once the loader inserts a round into the tube, he must then close and lock the venturi. If the venturi is not locked, the M2 cannot fire. The firer disengages the safety catch and has a two-pressure trigger to fire the round. The mechanical firing mechanism consists of a hand-cocked, percussion-operated detonator. Typically, the loader carries a total of four rounds.
The standard HEAT round (FFV551) has an effective range of 400 meters (1,312 feet) against moving targets and 500 meters (1,640 feet) against stationary targets. The HEAT round is capable of penetrating up to 400mm of armor plate. The M2 can also fire high-explosive (FFV441) and smoke (FFV469) rounds out to 1,000 meters (3,280 feet) in addition to a illumination round (FFV545) out to 2,000 meters (6,561 feet). The average muzzle velocity is 1,148 feet per second. A well trained crew can fire six rounds every minute.
The rounds consist of the warhead and a cartridge case, the case closed by a plastic disc. When fired, the propellant's detonation creates gas pressure in the cartridge case that starts the warhead out of the tube. The pressure then ruptures the plastic disc which vents the gas out the venturi. The mass and velocity of the exiting round, combined with the rearward ejected mass and velocity of the escaping gas cancels out the recoil forces on the M2. Of course, this makes being behind the M2 highly dangerous out to 30 meters (98 feet) and even out to 75 meters (246 feet), the shock wave caused by the back blast can result in injury to the unwary or unprepared.
The M2 was later updated to the M2-550 which incorporated the FFV555 telescopic sight which includes a drum-operated coincidence range finder. The sight also includes a selector switch that automatically adjusts the aiming to account for the different rounds the M2-550 can fire. Once the range and round selection is set, light pulses within the sight assist the firer with the correct lead on the target to score a successful hit. The HEAT round for the M2-550 was also improved by fitting it with fins for in-flight stabilization, a rocket motor to boost range, and a Teflon slip-ring to reduce the spin effect of the tube rifling on the round thereby improving the performance of the HEAT warhead. This boosted the effective range of the round out to a maximum of 700 meters (2,296 feet).
The German Bundeswehr replaced the M2 with the Panzerfaust 3 recoilless anti-tank weapon in 1987 but still maintains a small stock of the M2 for the sole purpose of battlefield illumination. However, the M2 (along with the improved M3 and M4 models) still see front-line use with some 44 countries, a true validation of the success of the Swedish built weapon.
Primary Sources:
Bishop, Chris and Drury, Ian The Encyclopedia of World Military Weapons (New York: Crescent Books, 1988)
Hogg, Ian V. Infantry Support Weapons (Mechanicsburg: Stackpole Books, 1995)
Owen, J.I.H. Brassey's Infantry Weapons of the World (New York: Bonanza Books, 1975)
