The RCL is a breech-loaded, single shot weapon with tubular shape, used mainly for Anti-Armour and Anti-Personnel in Infantry support roles. It uses a wide array of munitions for different roles (AP, HEAT, HE, Smoke, etc.). When it is fired, instead of all the propellant blast following the projectile out the barrel, a large portion is allowed to escape to the rear, providing an inertial force to counter the inertia of the projectile.
Since recoil has been mostly removed, the heavy and complex gun carriage and recoil damping mechanism can be dispensed with. This allows the firing of a heavier projectile in a lighter and smaller weapon than would be practical with a recoiling weapon of the same calibre. The range and velocity is comparable to that of a normal light cannon, although the RCL is typically used to fire larger shells at lower velocities and ranges.
The RCL is usually man-portable although larger versions is mounted on a lavetage on its own carriage or in a vehicle,. Most RCLs can be operated by a single operator but the traditional way of using this type of weapon is by a crew of 2-3 (Gunner, Loader and at occasions a Munitions handler). The lighter versions can be fired from the shoulder either by standing, kneeling or laying down (prone position). The strive is for such a stable positions as possible and when laying down a bi- or tripod is usually used.
Unlike a rocket launcher which fires fin-stabilized rockets from a smooth bore, RCL rounds resemble conventional artillery shells. They generally have a rifling band to engage the rifled launch tube, spin-stabilizing the projectile (hence the term "rifle"). The "case" area of the shell can be perforated to vent the propellant gases which are then directed to the rear, as the base of the shell disintegrates as on the Italian “Falgore”. Another solution is to have a lid that seals the rear of the round and that burns up upon firing as on the Swedish “Carl Gustaf”.
This type of weapon was fist produced just before the outbreak of WW2 by the Russians, followed by Germany produced its own version of the weapon. The United Kingdom and USA soon followed. Technically, only devices that use a rifled barrel are recoilless rifles, smoothbore variants are recoilless guns. Despite its name, the recoilless rifles/guns do recoil noticeably and produces a great blast.
Other similar weapons are RPGs (Rocket Propelled Grenade launchers) such as the Russian RPG-7 and disposable rocket launchers such as the Swedish AT-4. The later is based upon the same principle as the RCL but both is usually nominated as rocket launchers.