A projectile mainly for drug delivery comprises a tubular body casing 1 which defines a cavity 2 for containment of a tranquilizing drug. The casing has an end plug 3 which coaxially supports a hollow needle 4 projecting forward through an ogival nose cap 5. The delivery end 6 of the needle 4 projects a short way beyond the cap 5. Located around the needle 4 towards the tip of the nose cap 5 is a gas producing detonator 7 fired by an impact fuse 8. Attached to the detonator 7 and the needle 4 is the neck g of an inflatable bag 10 of which an opposed end 11 is attached to the plug 3. The rear end of the cavity 2 has a piston 12 the rear end of which communicates through concentric passageways 13 and ducts 14 with the interior of the bag 10. The nose cap 5 is of a readily breakable plastics material or designed to assist retardation.