The issue you will have is the back of the cylinder is cut for half/full moon clips or 45 AR ammo. The 45 Colt will have a lot thinner rim thickness and will most likely headspace (or whatever you call the distance between the back of the cylinder and the recoil shield) will be too large to either have consistent ignition, or you might have the cases back out after firing. That could either render the case un-reloadable or cause some safety issues. S&W brought out their 125th Anniversary M25-3. It came with a cylinder for the 45 Colt cartridge, as well as one for the 45 ACP/AR cartridge. I have seen a few of the cylinders for sale, but you might think about finding the complete gun and trading/selling your M25-2 and getting an M25-3.
