The 500 AHR was designed by Ed Plummer of American Hunting Rifles in Hamilton, Montana. It is intended to push 535 to 600 bullets at 2400 feet per second to duplicate the ballistics of the 500 Jeffery but without a rebated rim. AHR makes custom rifles in 500 AHR using the CZ550 action.
The 500 AHR is what the 500 Jeffery should have been. An even more practical alternative is the 500 A-Square because the brass is more readily available.