Ok guys, I was given two shotguns over the weekend. Both were my dad in laws and he hasn't shot them in like 20 years. One I'm curious about is a Winchester single shot. 3 inch chamber... says Winchester Proof Steel on the side of it. Does that mean its ok to shoot steel through? I shot lead through it the other day and it works great.... improved modified choke on it and its fixed but I'll get used to that. Ideas?? Steel or not?