What is back-boring?
Better patterns and increased shot velocity help you hit what you're shooting at. A back-bored barrel is a shotgun barrel that has a bore diameter increased beyond maximum specifications. Increasing the bore diameter of a shotgun barrel greatly enhances its performance. A larger bore diameter reduces friction of the shot charge against the barrel wall. Instead of trying to overcome friction, powder gases expend more energy on the wad base, resulting in an increase in shot velocity. Because there is less constriction or pressure from the barrel walls on a shot charge, there are fewer deformed shot pellets. A greater number of ballistically superior round pellets in a shot charge gives you exceptionally uniform patterns -- delivering more shot pellets in the effective part of your pattern.
The effortless transition of a shot charge through a barrel with a larger bore diameter results in a reduction in perceived recoil. Every reduction in recoil results in an increase in shooting comfort. Therfore, less felt recoil makes your shooting more enjoyable.
Who benefits from back-boring? A first time hunter, seasoned wingshot or competitive target shooter all benefit from a back-bored shotgun. More uniform patterns result in better hits and more smoked targets.
Inside diameter of a 12 gauge back-bored barrel is .742 +/- .0015
To improve the performance of a Browning shotgun, we increased the bore diameter.
Winchester 2 3/4" - 1 1/8 oz. - 8 shot at 40 yards. Full choke. Back-boring gives you extremely uniform densities.