Gun perforator

Claim 1

IN A BULLET GUN ASSEMBLY FOR USE IN PERFORATING A WELL CASING OR THE LIKE, SAID GUN ASSEMBLY BEING FORMED OF A GENERALLY CYLINDRICAL BODY PROVIDED WITH AT LEAST ONE LATERALLY EXTENDING OPENING FORMING AN INDIVIDUAL GUN, THE OPENING COMPRISING AN INNER PORTION ACCOMMODATING AN EXPLOSIVE CHARGE AND IGNITION MEANS, THE EXPLOSIVE CHARGE BEING AN ANNULAR BODY HAVING A CENTRAL BORE THERETHROUGH AND AN ENLARGED OUTER PORTION IN WHICH IS REMOVABLY SECURED A GENERALLY TUBULAR BARREL MEMBER HAVING A CENTRAL BORE FORMING A BARREL WITH INNER AND OUTER ENDS, THE INNER END OPPOSING THE EXPLOSIVE CHARGE, A CHARGE COVER BETWEEN THE EXPLOSIVE CHARGE AND INNER END OF THE BARREL, THE CENTRAL BORE OF THE BARREL ADAPTED TO RECEIVE A BULLET, THE IMPROVEMENT WHICH COMPRISES: THE INNER END OF THE BARREL BORE HAVING A FRUSTO-CONICAL ENLARGED END PORTION, A REMOVABLE FRUSTO-CONICAL RESTRAINING MEMBER FORMED OF STEEL POSITIONED IN THE FRUSTOCONICAL ENLARGED END PORTION OF THE BARREL BORE, THE FRUSTOCONICAL MEMBER HAVING A CENTRAL BORE AXISALLY ALIGNED WITH THE AXIS OF THE BARREL BORE, A BULLET HAVING A NOSE AND SHANK PORTION, WITH THE FORWARD PORTION OF SAID SHANK PORTION POSITIONED IN SAID CENTRAL BORE OF THE FRUSTO-CONICAL MEMBER AND FORMING A PRESS FIT WITH THE INNER PORTION OF SAID BORE TO FORM A SUBSTANTIALLY GAS-TIGHT SEAL, THE REARWARD PORTION OF SAID SHANK PORTION EXTENDING INTO THE BORE OF THE EXPLOSIVE CHARGE, SAID FRUSTO-CONICAL RESTRAINING MEANS BEING EFFECTIVE TO ACT AS A GAS SEAL FOR THE REARWARD PORTION OF THE SHANK OF THE BULLET TO INCREASE BULLET VELOCITY AND PROTECT THE INNER END OF THE BARREL BORE AGAINST EROSION BY PROPELLENT GASES.