Skittles, not so much. But m&m's on the other hand..
In all seriousness though, it felt like I had to focus more on getting the trigger to break which lead me to have a weaker grip (having a tight grip while trying to break a slightly heavier trigger makes your aim unsteady, therefore heavy trigger = weaker grip so that you can hold the sights steady). It's not really up for debate whether a weak grip causes bttf, although this may NOT be the only cause. One hand shooting causes far more bttf. Just a theory.. I'm aware of the other "issues" like extractor/ejector/ejection port, but I think my theory may at least have some logic to it..