According to the Mauser factory specs. for Type A barrels, the contour was the same for all calibers from .250 to .404. with a barrel length of 600mm (23.6"). The muzzel should measure .575/.563 dia. My Type A in 7x57 is fitted with a front sight ring base available on Type A's which adds to that dia. The sight ring measures .625 dia. and should be the same on the other calibers.