I have done some searches on the net but couldn't find anything stating that the ZKK series were investment cast ,The Ruger 77s had static loads put on the actions, which caused lugs to come off in segments ,when the same loadings were applied to M98s and Springfields they sheared the lugs completely ,so its proof they are strong .Whether the BRNOs are forged as stated by De Haas and the finish is sandblasted /bead blasted to save on costs e.g polishing etc maybe .