At the first Southern Side by Side, I entered the .410 event with a Briley tubed 20 gauge Parker. At that time tubed guns were legal at the Southern. I knew the big boys would be using 3" ammunition, so I put some 3" in my bag. I shot the first station with 2 1/2" ammo because it was a series of easy straightaways from an elevated stand. I ran that station and for the rest of the shoot, I shot the 2 1/2" ammo, forgetting I had the 3" ammo in my bag. I had never shot any 3" ammunition in this gun, and, later I was to find that the Briley tubes had 2 1/2" chambers and would not chamber a 3" shell. I won the .410 event at that shoot against some talented competitors. My .410 shells were loaded with 1/2 ounce of #9 shot. As I recall, my screw in chokes were probably improved modified and full. At the time I entered, it was late in the day. J.D.Shank was in the lead at the time with a very high score. He asked if he could walk around the course with me. I said "fine", knowing he wanted to make sure I didn't pad my score. I had his score beat by a bird if I ran the last station, a series of rabbits. The trap was throwing broken birds, one after the other. After expending nearly a dozen shells on broken birds, I finally got some good birds and ran the station.