SHAPED PRIMER

A primer (10; 20) for explosives which comprises a shaped charge (12) of detonating material for use with initiating means which penetrates into the charge characterised in that said primer has a cavity (16) therein to receive said initiating means, and a shock attenuator (14) in the form of an insert (14) of inert material the density of which is less than that of the detonating material, the insert extending from the surface of the charge into the charge to a desired detonation region (34) and having a portion surrounding at least a part of the length of the cavity and defining an inlet (16.1, 16.3) for insertion of said initiating means, the density of the insert relative to the detonating material and shape thereof providing for improved detonation of the primer.