I'm pretty sure my misfire was cold related. I've thought about it every which way I could and this is the best I could come up with... I think what happened is that I used a bullet/sabot that required a little less than medium pressure to load. (Sorry, don't know how to describe it) Once I got outside in below 0 temperatures the sabot shrunk up so the primer gasses were able to escape around it and not enough pressure to ignite the BH209. I don't really know for sure though. Either way that was the first FTF or misfire I've had.