I was at the range today and shot 100 rounds of standard American Eagle 115 grain FMJ and about 12 rounds of Remington 115 grain +P JHP. After I got home and was cleaning the pistol I noticed this gouge in the top of the frame. This is on the top of the frame about 1 inch or so in front of the rear sight. The pistol seemed to shoot fine at the range. I'm not sure what this is. A piece of jacket? A piece of a spring? Any idea?