Frank,
I double checked the numbers I gave you earlier and I was correct on the arbor diameter, but I was off on the cylinder through holes.
I reviewed the spread sheet and remeasured the Colt's 2nd Gen this evening:
The arbors run a range of Ø.427 to Ø.431 with the average being Ø.430. The cylinder holes run from Ø.433 to Ø.436, with the average being Ø.434. The loosest fit I have is an almost new '60 with an arbor diameter of Ø.428 and a cylinder bore of Ø.436. The tightest is an 1861 with an arbor of Ø.430 and a cylinder hole of Ø.433. The Colt 2nd Gen is an arbor of Ø.429 and a cylinder hole of Ø.434.
Regards,
Mako