Recoilless Rifles are heavy, shoulder-fired, single-shot weapons that can be mounted on a tripod or a swivel mount to fire. they fire an exploding shell that causes an explosive blast whet they hit. Only one shell can be fired per turn, and loading another shell takes one turn. Inertia screens and skeinsuits halve the damage.
The name comes from the design of the round, which uses part of the exploding gases when fired to counteract the recoil, allowing for relatively light weapons to be developed.
(Cited form Star Frontiers: Alpha Dawn Advanced Rulebook)