Projectile (10) is for use with barrel assemblies of the type having a plurality of axially disposed projectiles within a bore and wherein discrete propellant charges are provided for propelling respective projectiles sequentially from the bore. Projectile (10) comprises expandable sleeve (11) encircling at least part of core (12). Sleeve (11) and core (12) have wedging surfaces (14) operable to deform trailing part (21) of sleeve (11) into sealing engagement with the bore in response to pressures exerted on projectile (10). When projectiles (10) are axially disposed in the bore, rear face (24) of the leading projectile cooperates with leading face (20) of the trailing projectile to define a discrete space about spine (23) for receipt of the propellant charge. Sleeve (11) is retained about core (12) during travel to the target.