Sweet. The rings and rail should be very close to their nominal dimensions. When set up properly, proper wire, wire speed and feed rate, they are slower than milling but hold tolerances to AT LEAST +/- .0002. in comparison a human hair is .005.
But will it fit in the car ?
That was part of why I got rid of my .300 Win Mag Mod 70. With the back seat down it had to fit between the front seats to get the trunk closed.