the main parts to a Shell [b]Ogive.[/b] The ogive is the curved portion that streamlines the front of the projectile and reduces nose resistance. [b]Shoulder.[/b] The shoulder is the point where the ogive meets the bourrelet. [b]Bourrelet.[/b] The bourrelet is the carefully machined portion immediately in rear of the shoulders that rides on the lands of the barrel. It centres the projectile in the bore and prevents wobbling in the barrel. [b]Body.[/b] The body is the major portion of the projectile. [b]Driving Band.[/b] This is a band of metal or plastic that engraves into the lands and grooves of the barrel and imparts spin to the projectile. [b]Base.[/b] The base is the part in rear of the driving band. It can either be tapered (boat-tail), square base or hollow base. [b]Base Cover and Base Plug.[/b] The base cover is welded to the base of HE projectiles to prevent hot gases entering through tiny cracks or pores. The base plug is used in base ejection projectiles so the contents can be expelled. It may be connected to the projectile by threads, shear pins, twist pins or a combination of these.