Carl G. Mk 4

Vincent J. Curtis

11 Apr 21

The Carl Gustav recoilless rifle needs no introduction to Canadian infanteers.  The Mark 2 version was adopted in the 1960s as a replacement for the 3.5” rocket launcher for front-line anti-tank tasks.  It was succeeded eventually by the Mark 3 version, which was lighter in weight.  The Mark 4 version came out in 2017, which, at 6.6 kg (12 lb), is much lighter in weight than previous Marks.  The Mark 4 is made of advanced, lightweight materials, with the main tube being of carbon-fibre construction with a rifled titanium liner.  At 1000 rds before rebarreling, the Mark 4 has twice the life of the older steel versions.  It has provisions for a variety of sighting systems, including red-dot optics and with provision for future “smart-aiming” technologies of future warheads.

The original 84 mm version was developed by Sweden in 1948 as a replacement for an earlier 20 mm recoilless rifle developed for World War II.  That progenitor had many of the features of the Carl G, including the break action venturi.  Early in WWII, many nations used smallish calibre anti-tank weapons, such as the .55 calibre Boys anti-tank rifle, because the armour of early-war tanks were only proof against small arms.  By late war, tanks such as the Russian T-34 and the German Tigers and Panthers had frontal armour that was proof against all but high-velocity large calibre guns such as the British 17 pdr.

The first Carl G, with shaped charge warheads, was designed to be able to defeat the frontal armour of medium tanks of its era, particularly the T-34, and it remained relevant through the T-55s, T-62s and T-64s.  With the development of the Soviet T-72 and reactive armour, the limits of its shaped charge technology was exceeded, though tanks kills could still be achieved through side and rear shots.

A recoilless rifle is different from a rocket launcher.  A rocket launcher fires a rocket, and the entire assembly leaves the launch tube.  A recoilless rifle fires something like a shell, but a shell designed so that half the propulsion goes out the rear end of the tube.  Only half the propulsive force of the charge drives the warhead out the front of the tube, and rifling spins the warhead like a bullet, giving it stability in flight.  (Some warheads have additional fin stabilization.)  The balance of propulsive forces is what makes the rifle “recoilless.”  A closed-breech gun of that size would create too much recoil for a human to bear.  The muzzle velocity of the warhead is of the order of 1,000 fps, giving it good range.

Developments in warheads have expanded the Carl G’s usefulness.  Tactical munitions for the Carl G today can be divided into four categories: anti-armour, anti-personnel, anti-structure, and support.  Anti-armour are variations of HEAT warheads: the 551, 551C RS, the 751, and the 655CS.  Anti-structure rounds include the ASM 509, the MT 756, and the HEDP 502 and 502 RS.  These rounds open doors where none previously existed, or punch through outer walls and explode inside the structure.  Anti-personnel include the ADM 401, which fires flechettes, and HE 441D and HE 441D RS, which are longer range and intended for soft area targets in the open.  Support munitions include the ILLUM 545C and the SMOKE 469C.  Effective ranges vary a lot depending upon the application.

The unit cost of a Mark 4 is $20,000, and warheads run in price from a few hundred to a few thousand dollars apiece.  For $5 million, Canada could equip her army with 250 of these light-weight weapons, and a program of $10 million could give the army a decent re-equipment of modern, platoon-level anti-armour/anti-structure/anti-personnel capability.

Both Latvia and Estonia are users of the Marks 3 and 4 Carl G.  With Russia flexing its muscles around the Ukraine, Canada might contribute to deterrence by equipping the Ukraine with these low-cost anti-tank systems.  Better yet, donate our old systems as military assistance and re-equip ourselves with the new Mark 4.

-30-