"In the absence of contradictory data, collected and analyzed with the care used here, it is reasonable to conclude that good guns are insensitive to their bore diameters in the range of 0.724 inch to 0.745 inch and the near-universal move by manufacturers from the classic dimensions to the modern ones has not improved the patterns produced by their guns at all."

"This result is consistent with Dr. Jones' conclusion on page 153 of Sporting Shotgun Performance: 'The story of over sized (Back-Bored in this case) barrels is no story. The onus is on the proponents of Back-Bored guns to produce robust evidence in support of their claims. I think it is unlikely that any will be forthcoming.' " - Neil Winston.

This is something that has been going on for decades, with no end in sight. The unsubstantiated, unproven claim of "back-boring," or using larger than standard bore diameters, continues. Yet, there is no scientific evidence to back up the claims of improved pattern efficiencies and no supporting data from the manufacturers and other entities that publish these claims.

Even though there is nothing to show that a larger than standard bore diameter does anything beneficial for patterns, it persists. There was no discernible pattern efficiency increase with my Stan Baker MoneyMaker 303 barrels years ago and nothing has changed, in that regard, today.

Tell a fairy tale loud enough and long enough, sometimes it gets blindly accepted as fact. This has been the case with oversize bore diameters to an unprecedented extent.

The Browning brand has been the most effective proponent of back-boring. Browning, more than any other manufacturer, has made a larger than standard bore sound beneficial.

Due to the acceptance of the notion that a bit larger bore somehow improves patterns, Beretta and many other brands were forced to oversize their bores in one way or another. This door swings both ways, for Benelli has their standard bore, called the "Power Bore," but swings things back to slightly over-sized bores for the pricey "Performance Shop" branded guns.

This is not to suggest that shotguns with larger than standard bores don't go bang and spew pellets; of course they do. However, there is no verifiable evidence that shows they do anything that improves patterns.