Sup every one this happened to me yesterday and I thought I'd share it. I went to the range with by buddy and my cuz. I had brought my G-23 and my lonewolf 40 to 9mm barrel. We shot about 100rds of 40 then I was going to switch over to the 9mm barrel. I loaded up some mags and walked up to the line taped, racked, aimed and fired. Wait something didn't feel right....... ****. I just shot a 9mm round threw my 40 barrel. Now it didn't do any damage and the only thing hurt was my pride for making such a stupid mistake. All I'm taking with me from this stupid mistake is that soon as your stop paying attention for one second you could make a mistake that could hurt your self or someone around you.