I looked up your battery and it does say that they are a 4mm female bullet connector on the site. I have not heard of any problems with that end being too small. I have only heard of 4mm and 5mm bullets but could be wrong. The site does show a updated version of your battery on there. Maybe the older model runs 3.5mm? Others would have to chime in there. But I would not recommend filing out the insides.