Years ago I started shooting, lining up the front bead in the rear notch and setting the front bead at six o'clock on the target. this system gave-way to changing out the rear notch for an aperture and the bead for a flat post. With technology the irons gave-way to metal tubes with glass and reticles, but the common feature was that all these involved rifled barrels and bullets measured in thousands of an inch or millimeters. As my outdoors activities increased shotguns were added to the list. Following my rifle experience of looking down a single barrel, the same mindset was used in shotgun selection. The purchase was an Over-Under and many squirrels, upland and migratory birds fell to it. I seemed perfectly happy with the single sight-plane arrangement. Then I met a Winchester Model 21, followed by a Parker DHE. Suddenly, the O/U found itself sitting in the safe as a SxS accompanied me whenever I was going to the range or field. With the availability of Non-Tox shot suitable for migratory birds and old shotgun barrels, if I go goose hunting, I'll be using a SxS. So with the rapid transformation of decades of use of single plane shotguns over to the SxS double, I can only wonder: how long will it be before the bolt action rifles are left in the safe and I'll be carrying a SxS rifle while stalking big game in either the local woods or far away places?