Frank,
I have shot quite a few of the CT Ballistic Silvertips in my .270, the coating is Lubalox I don't really know what it does but there is no noticeable build up in the bore. I have had great luck with them but I have never noticed any significant differences between them and the regular Ballistic Tips but I never looked really closely either. Grab a box and give them a whirl, if you have a .270 I might have a few laying around I could send you to try.

Bob