What some guns get away with, others won’t. The lead in the cone can be thought of as cone repair which is why guys that competed cried when it built up so much they were forced to clean. Bullet / lube change is DEFINITELY an option if you aren’t satisfied. While powder heat that won’t melt lead will almost always melt lube that is exposed to it, thus you end up shooting an unlubed bullet up the pipe. This distance is end shake + barrel cylinder gap + cone depth. The less the angle, the deeper the cone. A wadcutter is the longest bearing length cause nothing is wasted on a nose, so it might work .... or not.
I am a stickler for clean too. I have a couple a guns with 3 - 4 thousand rounds that are due. From decades of doing this, the people with the most problems with cast are those that want to shoot cheap, those that want to shoot clean, & those that don’t shoot enough to learn the guns secret. You might be better off buying coated bullets instead of lubed “for THAT gun”. Interesting. I have never lost the bluing on a cylinder face before on any gun but I have worn the rifling away on a couple. No rules.