I was thinking that mineral oil/vaseline did not mix well with BP, but may be remembering something else. I would look to olive oil in the mix. If using long term, I would go with extra virgin, it takes much longer to go rancid. Jojoba oil, is silimilar in composition to whale oil, but it freezes at ~7 C. I do not know if that is a hard freeze, or not. Olive oil starts to solidify at -6 C, and not hard until a few degrees lower. A beeswax/olive oil mix works well. Normally I go 50-50. If that is your base and used during warmer months, a smaller amount could be taken and mixed to be 20-80 wax/oil. It would not be so hard as to impede loading. Just my hypothesizing. I was a food oil chemist 1989-1995, but moved to other chemistry.