Top: Smith & Wesson Model 37 with old flat latch. Bottom: Charter Arms Undercover.
- The width and height of the two guns are identical to within a few thousandths of an inch.
- The hammer & trigger on the Smith & Wesson are 6.2mm wide, whereas those on the Charter Arms are 7.7mm wide.
- Though the cylinder latch mechanisms differ, the two latches look very similar.
- The Smith & Wesson cylinder turns counterclockwise, whereas the Charter Arms cylinder turns clockwise.
- The alloy frame Smith & Wesson weighs 387 grams (13.65 oz.). The steel frame Charter Arms weighs 451 grams (15.9 oz.).
- The Smith & Wesson has its firing pin on the hammer, whereas the Charter Arms firing pin is in the frame.
- The Smith & Wesson has a side plate on the right side, whereas the Charter Arms has no side plate.
- The Smith & Wesson has an under-lug on the barrel to protect the ejector rod. The Charter Arms has no under-lug.