Patent ID: 8769795

Claim:
A method for making a well perforating gun to have rust resistance and gripping surfaces, the method comprising: a. forming a gun carrier comprising: (i) a gun wall annulus and an outer surface; (ii) a first threaded section formed in the gun wall annulus proximate a first end of the gun carrier, and a second threaded section formed in the gun wall annulus proximate a second end of the gun carrier; and (iii) a first seal bore formed in the gun wall annulus between the first threaded section and the first end of the gun carrier, and a second seal bore formed in the gun wall annulus between the second threaded section and the second end of the gun carrier; b. forming a charge loading tube configured to engage within the gun wall annulus, wherein the charge loading tube comprises: (i) a charge loading tube inner surface; (ii) a charge loading tube outer surface; (iii) a plurality of charge holes disposed through the charge loading tube; and (iv) a plurality of rear charge holes disposed through the charge loading tube, wherein each rear charge hole is concentrically aligned one of the charge holes; c. forming a first end cap disposed on a first end of the charge loading tube, and forming a second end cap disposed on a second end of the charge loading tube, wherein the end caps have a diameter larger than the charge loading tube outer surface forming a gap between the charge loading tube outer surface and the gun wall annulus when the charge loading tube is engaged within the gun wall annulus; and d. applying a first coating over the gun carrier, applying a second coating disposed over the charge loading tube, and applying a third coating over the end caps, wherein the first coating, the second coating, and the third coating are configured to prevent rust or forming a first gripping surface on the outer surface of the gun carrier proximate the first end of the gun carrier and forming a second gripping surface on the outer surface of the gun carrier proximate the second end of the gun carrier.