Askins discusses the bore dimensions of the best barrels they did in his book "Modern Shotguns and Loads." Except for a few thousandths more choke, the bores of my Super-Fox measure just as Askins describes in "Modern Shotguns and Loads" 1929, Small-Arms Technical Publishing Co., top of page 82. However, mine came from the factory chambered for 3-inch shells, and Askins was describing a 2 3/4 - inch chambered gun. Bore .738 inch to within 5.5 inches from muzzle, then tapered for an inch into enlargement to .740 inch, thence at 4.5 inches from muzzle choke constriction starts narrowing regularly to a choke constriction of .692 inch. The total constriction was therefore .048”. In my gun the total constrictions are a bit more at .051” left and .053” right.
