Fin-stabilized projectile having a sabot base and forming a practice projectile

Claim 1

A practice device having a sabot-driven sub-caliber fin-stabilized practice projectile, said device comprising: (a) a sabot base, said sabot defining a longitudinal axis within a barrel, said sabot having; (i) a passageway for propellant gas; (ii) a longitudinally driven piston mounted within said sabot, said piston driven from a first position to a second position by propellant gas passing through said passageway; (iii) first coupling means securing said piston to said sabot in a first position until a predetermined gas pressure is developed behind said piston to shear the first coupling and drive said piston from said first to said second position, (b) a sub-caliber fin-stabilized practice projectile mounted on said piston, said projectile having; (i) a projectile shell having external fins; (ii) a projectile head driven by said piston, and (iii) second coupling means for securing said projectile to said piston, said second coupling means being sheared by momentum imparted to said projectile head by the piston as it terminates its travel at its second position, whereby propellant gas expels the sabot from a barrel while simultaneously driving said piston from its first position to its second position and thereby launch the projectile by momentum imparted from said sabot and said piston.