I bought a32cal drop in bbl from GM and in the manual it said not to use wonder lube.I e-mailed Gm and the reply said ok to use on patches but not as preservative,because,in their experience bore butter trapped moisture causing barrel damage.I certainly won't dispute GM but I have used WL and Borebutter for years with great success and no rust.IMO proper drying is the problem, any lighter than water lube would possibly cause the same problem,except for WD40 or Ballistol or some other water displacing lube.Has anyone had this problem using WL or similar products?