I haven't tried them yet myself, I just know with the nickel builds in general, it's all about solid connections. That being said, I know that the STM is finicky to begin with and the coils in general need to be sinched down pretty good. Also, without knowing it, sometimes when you try to clean out and dry the base, the 510 pin moves a little. Try to gently press it back up into the base and keep good contact with the coil. I know mine have a slight bit of play in them!