holder 14 the shell holder 14 is inserted into the charge holder at said slot 52 and is secured into place by a set of allen head set screws holes 53 are drilled horizontally into said shell holder 14 near said slotted end and threaded to accept said allen head set screws a flat bottom shallow hole 54 is bored into the center of the slotted end 52 of the shell holder 14 perpendicular to slot said hole being larger than the center hole 51 which is bored through entire length of shell holder 14 this enables a charge holder to be secured into place yet leaves sufficient room to insert a detonating cord in the area numbered 27 and into the center hole 51 of the shell holder 14 o rings are placed in the o ring grooves 19 and 20 so that an appropriate seal will occur when the percussion firing assembly is placed into a hollow charge carrier near the middle of the shell holder 14 holes are drilled perpendicular to the center bore of said holder 14 the first hole is drilled directly in line with the milled slot 52 and the remaining holes at every 90 u00b0 around.