I have 1/8-27 NPT as being around 0.3268 in thread depth for a tapped hole as our standard when I design, program ,and machine here at work. If you can get a caliper that has a depth gage, check to see roughly the depth of threading in your valve. 1/8 NPT is tapered so the depth of threading determines greatly how far your mating fitting will go in. Too deep and the fitting will go in too far and not tighten up and not deep enough, the fitting will only go in a turn or two. Sounds like you have the later problem. So either your hole on the valve isn't tapped deep enough, or your fitting is a tad wonky. Out of the two issues though, at least your fitting tightens up. It can be fixed, either by chasing the threads on the fitting with a die or running a tap into the valve a turn or two more. Either or, be careful and go slow in small increments which ever way you decide to go. Its easy to oversize an NPT hole or undersize a fitting. I would make sure the fitting isn't the issue before I touched the valve though. I've had over 50 something 'Mags and never had a side hole issue with any of the valves but then again, never used CCM fittings either. It may be that Mag valves ran a little shallow to compensate for brass or standard macroline fittings vs. the more precise CCM fittings. Good luck, hopefully that helps. Bill will take care of you either way I'm sure. CCM are good peeps.