Rifles fire single projectiles. Shotguns fire dozens to hundreds of loose
pellets. Unless you're one heck of a great shot, you'll hit moving game with a
shotgun much better than with a rifle because all those pellets spread out to
create an "impact circle" of about 30 inches. Besides, it's against the law to
shoot flying birds with a rifle!
Shotgun pellets, commonly called "shot," spread because no round pellet is
perfectly round. Imperfections on each surface catch the air, so pellets plane
and deflect in the wind. Because they're launched at somewhere between 1,100
feet per second and 1,700 fps., there's a lot of
headwind to mess things up.
Throughout shotgunning history shooters have tried
to keep pellets together in a "tighter pattern." This enabled them to take
birds farther downrange. In the old days, a charge of shot was lucky to remain
effective to 25 yards. After that the pellets had spread so far apart that many
birds could fly between them.
Something else that changes shot pattern density at all distances is pellet
hardness. The harder the pellet, the smoother and more consistently round it
should be and remain after firing. When a stack of pellets within a shotshell are suddenly launched, they suffer significant
G-forces, which squashes them together. Soft pellets
get flattened. Hard pellets, less flattened. This is
one advantage of steel shot over lead shot. It resists deformation. But it
suffers from something else that hurts downrange performance. Insufficient mass.
The lighter any pellet, the faster it slows due to air drag. Tiny pellets lose
penetration energy quickly beyond 25 yards. Larger pellets maintain it.
Material density also contributes. Because steel shot is light (has relatively
low specific gravity or mass) it loses velocity and energy quickly. Lead is more dense, so it carries energy farther. But it's softer,
thus deforms more and blow open patterns. (Compromises,
compromises.) Some exotic shot, such as Hevi-Shot
shot, is even more dense than lead, so it really
reaches out. But it's expensive, too.
Shotgun Wads Protect Shot
Another way to combat pellet deformation is with wads. A shotshell
wad is a plastic "shell within a shell." It does at least four things.
1. It isolates the shot from the powder;
2. It protects the shot from scraping against the barrel walls;
3. It cushions the shot upon ignition, absorbing some of the shock to reduce
mashing under G forces, and;
4. It holds the charge together after leaving the muzzle to increase pattern
Some wads do this better than others, which is one of the major differences
between brands and types of ammunition.
Given the right choke, shell, wad, and type of pellets, any gauge shotgun
can maintain tight patterns equally far downrange. So, a 20-gauge can pattern
as tightly as a 12-gauge. But a 12-gauge will remain effective much farther
(say 15- to 20 yards) downrange simply because it starts out with a larger
payload. A 3-inch, 12-gauge can throw 264 No. 4 steel pellets; a 3-inch,
20-gauge can spit only 192 No. 4 pellets. Advantage, 12 gauge.
Different guns and chokes will handle different shotshell
loads differently. This is why serious shooters are urged to test pattern
consistently by shooting into large (3-foot x 3-foot feet) sheets of paper or
cardboard at hunting ranges (25- to 50 yards) to check for pattern density and
consistency. Buy the ammo that performs best in your gun.
Shop The Sportsman's Guide for a great selection of Shotgun Ammunition!
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.