Mostly a Series 80 Gold Cup, fit to a Caspian barstock frame. Hammer is a standard, round-hole Commander type, trimmed into a short spur. Grip safety was trimmed and blended to match the frame contours. Kart EZ-fit barrel and bushing. I did the work on those parts.
The Wilson sight was installed by Angle-Bore, and the blue finish by JPL Precision.
Here's the "internal magwell", that I did with files and a dremel