The High-Low system also referred to as the "High-Low Pressure system", the "High-Low Propulsion System", and the "High-Low projection system", is a design of cannon and antitank launcher using a smaller high-pressure chamber for storing the propellant. It enables a much larger projectile to be launched without the heavy equipment typically required for large caliber weapons. When the propellant is ignited, the higher pressure gases are bled out through vents (or ports) at reduced pressure to a much larger low pressure chamber to push the projectile forward. With the High-Low System a weapon can be designed with reduced or negligible recoil. The High-Low System also allows the weight of the weapon and its ammunition to be significantly reduced. Manufacturing cost and production time are drastically lower than standard cannon or other small-arm weapon systems firing a projectile of the same size and weight. It has a far more efficient use of the propellant, unlike earlier recoilless weapons, where most of the propellant is expended to the rear of the weapon to counter the recoil of the projectile being fired.