i've got an issue with just one mod here where everything screws down perfectly but it won't recognise nautilus or my triton mini which is why i asked. But what you're saying Hawise is very unusual. I think Eskie is on to something here.. some atomizers just DON'T screw down all the way, especially if the 510 outer ring is slightly raised on the mod. Also if the 510 pin hole is shallow without much spring (joyetech anyone for a shallow example - on my wismec and joyetech, nothing aspire or kanger can screw down anywhere near all the way here). If that's what you mean, then that happens to a variety of tanks on a variety of mods.. but the way you are saying won't screw down, comes across as if it literally won't screw down at ALL, which i have never heard of before, ever. I just checked my supertank here, and it works perfectly on my arhon which is the exact same chip and 510 as the NX other than being beefed up watts wise. There is a gap though. Is that what you mean?