Kids ask the wisest questions: “Why are shotgun names and numbers so weird,” a nephew wondered.
“Because ‘old fashioned’ people invented them,” I said. But he needed more explanation than that. We all do.
First, shotguns are measured by gauge instead of bore diameter. Gauge is determined by melting a pound of lead into individual balls that fit the bore diameter of any gun. The fewer balls to the pound, the lower the gauge number, but the bigger the bore size.
Like the nephew said, weird. So if one pound of lead yields 12 balls that fit the bore diameter, it’s a 12 gauge. Twenty balls means it’s a 20 gauge and so on except (there’s always an exception, eh?) the .410, which really is a bore diameter of .41-inch. If you were to melt a pound of lead into .41-inch balls, you’d get 68 of them — a 68 gauge.
Back when guns were made one-by-one, barrels often came out with odd bore sizes, so folks hunted with 17 gauges, 24 gauges, even 8-, 5- and 4- gauges. Those last two would knock you on your butt, believe me.
Today things have settled into just a few common shotgun sizes. Starting with the largest, there’s the 10-, 12-, 16-, 20-, 28-, plus the tiny .410 bore.
Another way to understand this is to match the gauge to actual bore diameter, like this:
10 ga. = .775-inch
12 ga. = .729-inch
16 ga. = .663-inch
20 ga. = .615-inch
28 ga. = .550-inch
.410 = .410-inch
So, the lower the gauge number, the bigger the gun. But that’s hardly the end of the numbers.
There’s barrel length, too. For hunting these generally run from 24-inches long to 30 inches. Most hunters favor a 26- to 28-inch barrel. Longer barrel shotguns do not shoot farther or hit harder, but they maintain momentum, which helps shooters maintain a critical “follow through,” which prevents stopping the swing and shooting behind a moving target. Some turkey hunters like shorter barrels because they’re easier to carry through thick woods. Most turkeys are shot in the head as standing targets, so “swing” has no bearing on success.
Which gauge is best? Depends on your needs. The larger bore sizes can fire more shot (pellets) and handle larger pellet sizes more efficiently, so the 12- and 10 gauges are better for throwing big pellets at big birds such as geese. Smaller bore sizes make for lighter, faster handling guns, so they’re better when you need to shoot quickly at grouse or quail. They perform best with smaller pellet sizes.
It’s important to know that large gauges do not necessarily shoot faster or farther than small gauges. The total weight of the payload (shot charge) is driven to relatively standard velocities in all gauges, and pellet size determines how much energy each pellet will retain downrange. But, because large gauges start out with more pellets in a charge, they can hit harder by delivering more pellets to the target. But that doesn’t always happen. Why not? Blown patterns.
When hundreds of pellets in a charge of shot fly downrange, they spread out. The farther from the muzzle, the wider the spread of the pattern. It’s possible for a 20 gauge to put more of a given shot size on target than a 12 gauge, depending on factors such as choke, pellet hardness, wad configuration, and more.
As a general rule, the most versatile shotgun these days is a 12 gauge chambered to handle 3-inch shells. That means you can also shoot 2-3/4-inch shells through it. By selecting different charge weights from 1-ounce to 2 ounces, and shot sizes from 9-shot (small) to BB (large,), you’re set for just about any bird that flies or bunny that bounces.
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Ron Spomer has been photographing and writing about the outdoors for nearly four decades. He’s written seven books, hunted on six continents and been published in more than 120 magazines. He’s currently rifles’ editor at “Sporting Classics,” Travel columnist at “Sports Afield,” Field Editor at “American Hunter” and “Guns & Ammo” — Optics Columnist at “North American Hunter,” Contributing Editor at “Successful Hunter,” Senior Writer at “Gun Hunter,” and TV host of “Winchester World of Whitetail.” He will write on Shooting Tips weekly for sportsmansguide.com. You can read his blogs and catch some of his YouTube videos at www.Ronspomeroutdoors.com.