Just bought my first AR15 (First rifle of any kind, save my 10/22). Took it out shooting today. Round count (very approx) 125 I was shooting semi-quickly...maybe 1 round every 3/4th of a second. I pulled the trigger ONCE and heard two distinct shots much much faster than I would have been able to it myself. I stopped shooting and looked at my buddy, who was watching me and was visibly confused by the double shot as well. Is this "normal"? I attempted to do it a few more times and couldn't even come close. Thanks for the info.