An arrangement for recoilless launch including a non-gaseous reaction mass having a weight in a range of about 25% to about 75% of a weight of a projectile. For the same projectile energy, less propellant is required than a rocket, which minimizes backblast and reduces before-launch weight. The recoilless launching is adapted to shoulder-launched projectiles in a confined space. The reaction mass may be particles associated with a propellant so as to be released concurrently as the propellant turns into gas and accelerated by and with the propellant gas in a nozzle.