In the context of double-barreled shotguns (side-by-side or over/under), “regulation” refers to how the two barrels are aligned so that they both shoot to the same point of impact (POI) at a specific distance.
What “Regulation” Means
Shotgun barrels are not perfectly parallel. Because each barrel is offset from the bore centerline, a gunsmith must adjust their angles during construction so that:
Both barrels’ patterns overlap at a chosen distance (usually 40 yards for field guns, sometimes 21–30 yards for skeet).
Vertical alignment (over/under barrels) is correct.
Horizontal alignment (side-by-side barrels) is correct.
This ensures that when you fire either barrel, the pattern hits where you’re aiming.
