I just gifted a IBT and a couple of IKV platinums to one of my soldiers to use on his vamo, got tired of listening to him whine about his vivis being crap. We slotted the top cap of his vamo with a dremmel, (can get the tank damn near flush)That thing is a vape bomb now. Check your carto like Baditude said. I have had horrible luck with flanged cartos, lots of duds, mabee it's like a lot of vape gear, one company churning them out for everyone else to re-brand as theirs and their QC sucks, I don't know. I stick to single coil cartos now.