Since 10 gauge hulls are expensive and hard to come by, I bought a set of adapters to fire 20 gauge 2 3/4 shells out of. So far they have worked well, patterning beyond expectation. The only problem is HUGE reduction in velocity and a lot of smudge and carbon everywhere. I was curious as to anyone else's experience with them has been, and one question, does constantly using the steel inserts, even with oil, ever mark, wear or do anything bad to the chambers with repeated use?