One rather alarming aspect of many of the greases used to protect bores is that the greases turn brown while the gun is stored. That first pass in preparation for shooting comes out with a very rust brown patch. This is especially true of a heavily greased Bore Butter application. It doesn't help the Bore Butter case since it's not the greatest rust inhibitor. A rust inhibiting lubricant is still needed. And cleaning patches will still come out brown.
Greases turning brown are probably one of the reasons many "rusty" barrels clean up and shoot okay.
Greases turning brown are probably one of the reasons many "rusty" barrels clean up and shoot okay.