My bore slugs at .301-.311. Ok i tried .312 cast Hi-tek coated boolits all kinds of recipes. The gun just does not like cast. So i ordered some Berry's .311 123 grain spire tip. It does well with those. I also have Berry's .308 150 grain for my 30.06. I loaded 5 of those for the mosin. And hit my steel plate at 100 yards with those 3 out of 5 rounds open sights. My question is will the .308 harm the bore? I cleaned it after my outing no signs of copper fouling.