SPJ
Not quite. The original COLT guns, be they 1860 or Open Top were NOT converted to 45 Colt. Cylinder is just too small. The Colt guns of the day, were chambered in 44 Colt. 44 Colt was not a .44 the 44 Colt was loaded with a heel base bullet to fill the 1860 45 Bore (which wasn't really 45) and the Open Top was similar, chambering 44 Henry Flat or 44 Stetson. Outside lube heel base bullets.
I'm trying hard to figure out what you're trying to accomplish. Trying to get 6 rounds in Colt pattern 1851 or 1860 frames just isn't mechanically sensible. Were you to fully rebate the water table, you would also have to alter ALL of the parts of Lock Works. So WHY are you so determined to try and do something that is completely impractical.
If what you desire is something comparable to 19th century Ballistics/Performance and to be able to shoot the same cartridge in Rifle and handguns, there are much better and more practical ways to accomplish it. Select ANY of the Toggle Link lever rifles, add a Smith Shop short cartridge Carrier Block and away you go. You can run Cowboy 45 Special cases in any of the Toggle Link rifles so modified. Then run the same cartridge in any of the commercially .45 chambered Conversions or the Open Top. Or, same carrier, in an 1866 or 1873 chambered for 44 Special and just run 44 Russian cases. Same same with 44 Special conversions and Open Top.
Or. Are you just determined to try and do something the most difficult and expensive way possible?? Regardless, you not going to get 6 45 Colt cartridges in a period dimension cylinder. Unless of course, you really do want it to blow up in your Hand??
Hide and Watch
PS: Can I have the Peanut and Popcorn concession for the attempt??