This profile is the same as many early barrels, including woodsrunner. I took the dimentions from woodsrunner and gave them to Ed Rayl, and it has become one of his standards now. The breech taper allows for a nice flare to the wrist of the gun, but then tapers to a smaller mid area, and allows for a well balanced finished weapon. The muzzle dim. allows for the rear sight to be placed well up the barrel, and easier for those of us with older eyes. This is my favorite barrel profile, whether in it's original size, or scaled down for a 1 1/16 breech.
Dan