Lagopus, in answer to your question about my experience shooting steel in my AYA 10: The original chokes in this gun were about .045 in both barrels and I never enlarged them. I was never able to detect any damage to the bores or the chokes. I've never similarly abused any of my other tens. I usually shoot them with chamber inserts and 12 gauge shells. I still have a small stash of RST tens, but I'm saving them for special occasions, like shooting my Winchester Model 01 lever gun.