I have a mini and recently had a similar problem. It would fire as it should at times and sort of weak or almost not fire at all sometimes. I have a very small magnet that I put on the positive end of my battery. I guess I'm just lengthening the battery to enable more solid contact. How can I remedy this problem? I bought the mini here on the forums in September of last year. It's the only mod I use now and I surely don't want to have to be without it. Thanks..
This is a longshot, but if you're using a battery spacer and getting intermittent contact, try moving the spacer to the bottom of the battery. It's possible the magnet is sliding around a bit on the top, moving the target for the firing pin.