Take your standard 2Kg CO2 FE. Take your standard D-D regulator. Looking at the FEs at work, how on earth does the regulator body clear the 'shoulder' of the CO2 tank when screwing into the thread at the side of the handle? Obviously not a problem on the 600gm bottles as the regulator is top mounted. Has anyone encountered this problem? Looking at it i just dont think my regulator would screw in to the side mounted thread without some part of the regulator (most likely the guage) touching the shoulder of the FE.