On the left is a Colt Detective Special, and on the right is the Kimber K6S.
You may be able to discern that the cartridge rims on the Colt are slightly further apart than on the Kimber,
you should also note that the Kimber cylinder is about 1/100 of an inch greater in diameter. A Safariland
six-shot speed loader works great on the Colt but will not fit the Kimber.