BudsGunShop.com - Can .45 Auto Rim be safely fired?

Jeffrey, Simple answer. No.
The rim of the 45 Colt cartridge is .060 thick. The rim of 45 Auto Rim is .090 thick. This is because when the 45 Auto Rim cartridge was developed, for the Colt and S&W Model 1917 revolvers, the space behind the cylinder was .030 more than with most revolvers to accommodate the moon clips that 45 ACP was usually clipped to. The .090 thick rim filled up the extra space so the Auto Rim round would headspace properly in a 1917 revolver.
There are modifications that can be made to the rear of the cylinder of a 45 Colt revolver, but as they come from the factory, almost every 45 Colt revolver will only have about .060 behind the cylinder and the .090 thick rim of the 45 AR round will not allow the cylinder to close properly.
I believe Ruger has a model out that will accept both 45 Colt and 45 AR because they have specially machined the rear of the cylinder.
But the standard, run of the mill 45 Colt revolver cannot chamber 45 Auto Rim.