I use 3F Swiss in my small bores. These guns are from 32 to 40cal. I have no issue at all with fouling. This is my experience, but Swiss is ideal for small bores. But, I really never had trouble though using Goex either. Over the years I have used allot of different lubes as well and I like patching/ball combos that allow for at least a .015 patch or thicker.