Originally Posted by KyJim
The C3 is a CCO-sized pistol (4.25 inch barrel and grip frame shortened by one inch).
The original Colt CCO was a hybrid, mounting a Commander (4-1/4") slide and barrel on an Officers ACP frame, which has a slightly shorter grip and one less round of magazine capacity. The difference in grip length is, however, nowhere near one inch. Measured perpendicular to the rails, the difference is 0.3625 inches. Measured along the axis of the magazine well, the difference is 0.3838 inches. In other words, of an order of magnitude of about 3/8 on an inch, not one inch.