Hunting Arms and Ammunition: Shotguns
Shotguns are used for all sorts of hunting, from close range big game to wingshooting. When used with single projectiles, rifled slugs or sabot-clad bullets, they are used like rifles. Shooting shotguns with single projectiles involves careful aiming or sight picture control and trigger control for accurate shot placement. For other purposes, they are designed to provide an adequate cloud of shot with enough energy to cleanly kill the species being hunted. Timing and follow through are critical to hitting moving game effectively with a shotgun. The gun should swing smoothly and shoot where you are looking. The skilled hunter must learn to select the combination of gauge, choke, and load to match the game and conditions under which it is being hunted.
Gauge
Shotgun bore diameters are designated by gauge. Formerly, the gauge of the gun was the number of lead balls, just bore diameter, that could be cast from a pound of lead. Thus, a 10 gauge, the largest on currently in use, held a ball that weighed one-tenth of a pound. Bore diameter lead balls for a 28 gauge weighed one-twenty eighth of a pound. The larger the gauge, the smaller the bore diameter. Today shotgun bores have been standardized by arms manufacturers, with 10, 12, 16, 20 and 28 gauge arms and ammunition readily available in the United States. The .410 bore is the smallest shotgun generally available, but it is a caliber rather than a gauge.
Generally, the larger the bore, the greater the maximum shot charge available. For example, many manufacturers offer tow ounce leads for 3 ½-inch 10-gauge loadings. The normal charge for a 28-gauge gun is ¾-ounce. In addition to having a larger “payload,” larger bores tend to have a shorter shotstring with similar loads. Shot would tend to be strung out further in a 1 ¼-ounce 3-inch 20-gauge load than it would in a 12-gauge load of the same weight. The shorter shot string may increase the effectiveness of a load under hunting conditions.
Safety Conditions
Shotguns are made with several chamber lengths. Modern shotguns in 12 may have 2 ¾, 3 or 3 ½-inch chambers. In 20 gauge the chambers may be either 3 or 2 ¾-inches, and .410 bore chambers are usually either 3 or 2 ½-inches in chamber length. The longer cases used can hold larger shot charges, making the guns more versatile. Some older 10 gauges may have 3-inch chambers, and some 16-gauge guns may have 2 7/16-inch chambers. It is safe to fire shorter shells in long chambers but very dangerous to fire longer cases in the shorter chambers. [Note that only fluid steel barrels should be used with modern ammunition – no Damascus barrels.]
When hunting with a shotgun, the hunter should carry only one gauge of ammunition at any given time. Several gauge combinations can cause dangerous bore obstructions. The most common combination is a 20 gauge in a 12 gauge. The smaller case will lodge just beyond chamber of the larger bore, causing dangerous pressures and a possible burst barrel. Other combinations are equally dangerous – 28 gauge in a 20 gauge and a 16 gauge in a 10 gauge.
Chokes
Early shotguns had uniform bore diameters from chamber to muzzle. Someone discovered that constricting the bore a small amount caused the shot charge to stay together longer, increasing the effective range of the shotgun. Chokes were used in a variety of ways. Jug chokes were made by slightly increasing the inside diameter of the barrel just before the muzzle. Swaged chokes were made by forcing the muzzle into a tapered jig, constricting the bore slightly. Machined chokes are cut with a reamer. They may be tapered or parallel. Recently many manufacturers have produced choke tubes that could be screwed into the threaded muzzle of the shotgun. They are an advancement of variable choke devices, which could be opened or tightened by turning a collet.
The most commonly encountered chokes are skeet, improved cylinder, modified and full. True cylinder has no choke. Most slug barrels are built to snug cylinder full length. Skeet chokes are designed for optimum patterns at about 22-25 yards. Improved cylinder is designed to be best at 25-30 yards. Modified chokes are best at about 35-40 yards. Full choke is designed for 40 yards and beyond. Other borings include ¼ choke (strong I/C or Skeet 2), improved modified or ¾ choke (between modified and full) and extra full.
A pervasive myth in shotgunning is that longer barrels shoot “harder” and “tighter.” Barrel length beyond about 18-22 inches has little effect on velocity. Choke, not barrel length , determines shot dispersion. The major advantage of long barrels in long range shooting is having a longer “sighting plane” and a more muzzle heavy, smoother swing.
Shotgun Ballistics
All projectiles have kinetic energy when they are in motion. That energy is defined by the mass and the velocity of the projectile. In shotgun pellets, the range in muzzle energy is from about two foot-pounds to 225 foot-pounds. Usually shotgun patterns become too thin to assure hits before the pellets lose striking energy.
Pattern density is an interaction of shot charge, shot size, choke and distance. Larger shot charges hold greater numbers of pellets, yielding larger numbers of effective pellets in the pattern (usually measured in a 30-inch circle) at the same percentage. Larger pellets have more energy but their pattern is less dense than smaller shot. Shot size selection is usually a trade-off between energy and density. Increasing the choke constriction usually increases pattern density, but excessive choke may cause patterns to begin to open again. Finally, distance increases pellet dispersion. Shot hardness affects the degree to which pellets drift from the pattern. Softer shot, because of greater deformation (flattening) spreads more quickly than magnum, or hard, shot. All these factors figure in selecting a shotgun load for game.
The effective ranges of 12 gauge standard loads were listed earlier. Going to 3-inch magnums loads may add up to 10 yards to those ranges with similar shot sizes. Dropping down to 20 gauge reduces the effective range a few yards, perhaps up to 5 yards. The 28 gauge requires a reduction of about 5 more yards, with about 35 yards the maximum realistic range on game. The little .410 is a gun for experts willing to limit shots to 20-25 yards.
Shotgun Selection
Many factors contribute to decisions on shotgun selection for hunting. It may be merely what is available. We may have the opportunity to select whatever we really want. Cost and personal preference as well as intended use are major factors to be considered. Single shots of all action types are usually least expensive, but they are limited to a single round before reloading. Stock design on singles may have excess drop with rather strong recoil. Bolt actions are a bit more expensive and slightly faster on second and third shots than singles. Stock dimensions are much more rifle-like.
Slide or pump action shotguns are very popular. They are very fast, readily available in many models at a variety of costs, and adaptable to many shotgunning situations. Experienced pump gun shooters are as fast as semi-auto users, and the pump is usually lighter than a semi-auto. In addition, the pump gun may be more reliable under severe conditions where a semi-auto can become an expensive single shot. Semi-auto’s are fast, relatively reliable, and available in a wide variety of models and costs. Their extended action cycle and greater mass tend to soften felt recoil, a bonus to shooters when shooting is steady. The weight smoothes swings, but is a cost for the walking hunter.
Doubles, either over-unders or side-by-sides, are among the most expensive shotguns. They offer nearly instant choke selection because the barrels are usually choked differently. They have a shorter action that places balance between the hands without excess weight. Like break action singles, they are easily checked for obstructions or loads, making them very safe.
Selection is largely a matter of finding a gun that looks good to you, fits your shooting style and matches your pocketbook. Shooting where you look is very important. Matching the features to your intended use is also important. Specialized guns for special uses are available, but many guns fit a variety of purposes. Most skeet guns, for example, are excellent upland bird guns. Short, light guns are fast, but not very smooth. Long, heavy guns are slower but smoother to swing. Slug guns and turkey guns are usually relatively short-barreled. Turkey and goose guns are usually tightly choked and big bored. Pass shooting guns tend to have long barrels for smoother swings. Upland bird guns for dense cover are usually short and quick. Interchangeable barrels and screw=in choke tubes make most modern shotguns extremely versatile.
The 3 or 3 ½-inch chambered 12-gauge shotgun with screw-in chokes or interchangeable barrels is probably the most versatile shotgun for all hunting. The mighty 10-gauge is a heavy duty specialist for waterfowling, turkey, predators and perhaps deer. The 20 gauge with 3-inch chamber is an excellent and versatile lighter gun that serves well in upland or marsh. The 28 gauge and .410 are expert’s guns demanding good shooting and better judgment.
No matter what hunting situation presents itself, ethical choices are critical. Hunters need to keep their shots in a sure-kill range. Leads and ability to hit must be considered as does the density of patterns and pellet energy. Optimizing those factors reduces the chance of crippling or wounding loss.
Matching Tactics to the Game
Some species of wildlife are easy to stop or kill. Other species seem to be very tough and tenacious. Those species demand heavier, denser loads of larger shot for sure-kills and easy recovery. Squirrels, pheasants, turkeys, foxes, coyotes and most waterfowl are tough customers. Most other upland birds and rabbits are relatively easy to stop. Even they may need heavier shot when game birds or small game animals are heavily feathered or furred and layered with fat late in the season. Balancing loads to the work at hand is very important.
Big Game Shotgunning
Shotguns can be very effective big game arms within their effective range. Many states require shotguns either with slugs or buckshot. Both slugs and buckshot carry high energies and are potentially very dangerous down range. Therefore, backstops must be safe and sure. The notion that distance is an adequate backstop, so common to shotgunners, must be reconsidered in this situation.
When hunting with slugs, good sights and careful sighting in are essential. Shots must be kept inside the accuracy range of the slug/shotgun/shooter combination. For most of them, that means keeping shots inside 75-100 yards. Specialized equipment may be capable of a few yards more. Slugs from 10 gauge and 12 gauge guns have impressive energy and killing power. In fact, they are often the preferred choice for following up medium sized dangerous game that has been wounded. In contrast, the tiny 2 ½-inch .410 slug is underpowered and inadequate for use on big game.
Like slugs, buckshot has better potential as a big game load in big bore guns. Wise hunters will invest in patterning several sizes and brands in their gun/choke combination to be sure they are getting the best performance and to determine maximum ethical ranges. Caution on shot selection is essential with buckshot to make sure of clean kills and to minimize wounding. Careful attention to possible downrange hazards is also vital with these large, high energy pellets.
Summary
Most of the ammunition manufacturers have recommendations on shot size, choke, and load combinations for a variety of game. They are a good place to start in determining the ones that work best for you, but you may find that another combination fits your hunting style and game animals better. The only way is to try them in the field and to keep careful notes on your results. Good hunting!
