Abstract: A device for improving the aerodynamic feature of a projectile is disclosed. The projectile has a front part and a rear part. The external diameter of the front part of the projectile is larger than the external diameter of the front end of a rear part of the projectile. The front end of the rear part of the projectile is conical having larger diameter at locations behind the front end. The device comprises an annular cut-off cone sleeve slidably disposable over the front part of the projectile. The diameter of the narrower end of the annular cone sleeve is slightly larger than the diameter of the front part of the projectile and the length of the annular cut-off cone sleeve is larger than the distance between the front end of the rear part of the projectile and a location on rear part having a diameter equal to the diameter of the rear end of the annular cut-off cone sleeve.