United States, Regions, Divisions, and States: 1900 to 1990 [TXT] United States: 1790 to 1990 [PDF] NOTE: An error in the 1960 rural population count was discovered after the publication of CPH-2-1 from the 1990 Census. The correct 1960 rural population using the 'Current urban definition' is 54,054,425.
Shotgun Choke Tubes: A choke tube is; a removable interior tube at the end of a shotgun barrel that controls shot dispersion. Choke tubes typically come in cylinder, improved cylinder, modified, improved modified, full and extra full.A cylinder choke tube produces a very wide shot dispersion, whereas a extra full choke tube will provide a much tighter shot pattern. Different chokes are used for skeet, trap, and sporting clays.hoke tube selection is a confusing issue amongst a lot of shotgunners but one that is easily explained. Everyone knows how to pattern a shotgun and what they are looking for, which is the ultimate full choke pattern at 40 yards, which is a 70% shot pattern, it is this area where it all gets fuzzy and needs explaining.
A choke is simply a tapered constriction of the gun barrelâs bore at the muzzle end. The exit end of the choke is smaller by some dimension than the actual bore of the barrel. This difference is the amount of constriction. For example if the bore of the barrel is .730 and the exit dia of the choke is .710 you have a constriction of .020.