Abstract: A plastic composite sabot (1) includes an integrally molded rearwardly located deformable shoulder (6) which engages the grooves (10) in a rifled barrel (7). The sabot also includes mid and forward sections (4) and (5) which engage the lands (11) in the rifled barrel, and, an axially disposed projectile retaining chamber (13). An obturator (17), attached by pins to the sabot, drives the sabot and projectile through the barrel on firing. Utilizing a unitary plastic composite sabot substantially lessens manufacturing costs and increases projectile stability while reducing overall weight, thereby optimizing projectile velocity and accuracy while minimizing costs.