Air Gunomics

By Jim Low | September 20, 2010
From Missouri Conservationist: Oct 2010

Jeff Cox, age 14, made history on Oct. 5, 2008, when he bagged a whitetail doe in the west St. Louis County suburb of Wildwood. It was the third day of Missouri’s urban deer hunt, the earliest portion of Missouri’s firearms deer season, and 2008 was the first year in modern times when it was legal to hunt deer with air-powered rifles. As far as anyone knows, Cox was the first Missourian to take a deer with an air rifle.

You might be scratching your head wondering how he managed to kill a deer with a BB gun. That is exactly the sort of skepticism that Cox’s father, Ken, faced when he asked the Conservation Department’s Regulations Committee to make air-powered rifles a legal method for hunting white-tailed deer.

Like many adults, Ken’s interest in air guns began early. As a teenager, he hunted rabbits and squirrels with small-caliber air guns. His interest in air guns continued into adulthood, and he occasionally wondered when someone was going to develop an air rifle powerful enough for deer hunting. Then one day an online search turned up a large-caliber air-gun maker right here in Missouri.

It took several years, but he finally got his own .458-cal. rifle made by Dennis Quackenbush, of Urbana. Ken and Jeff have taken six deer with it so far, but before they could take aim at a deer, they had to score a bull’s-eye with a task force created by the Conservation Department’s Regulations Committee to investigate the matter. Ken was confident that the idea would sell itself if Regulations Committee members could see a large-caliber air rifle in action and shoot it themselves, so he took them to the shooting range.

Once they saw what an air gun could do, they were convinced. Starting in 2008, Missouri hunters could use air guns .40 cal. or larger for deer hunting, as long as they can be charged only from an external, high-compression power source, including external hand pumps, air tanks or air compressors. These requirements ensure adequate power for producing clean, quick kills.

To see what air guns were all about, I spent an afternoon with Ken and his air gun at the St. Louis County Police Range. What impressed me most were the rifle’s light recoil and minimal noise. I am used to the kick of my .30-06 Springfield, but I can’t say I am fond of the kick or the rifle’s deafening roar. The Quackenbush rifle barely nudged my shoulder when it spit out a cylindrical lead bullet weighing 425 grains (a tiny bit less than one ounce). The report was so mild, I felt a little silly wearing earplugs.

Ken’s deer rifle gets its power from a carbon-fiber tank containing air under 4,500 pounds per square inch (psi) of pressure. This is the same tank firefighters use to breathe in smokefilled buildings. A single charge is enough for three full-power shots. You can get more shots during target practice by using lighter bullets.

Ken’s 425-grain, hollow-point lead bullets are huge compared to the brass-jacketed bullets used in most center-fire rifles. My .30-06, a venerable favorite cartridge among deer hunters, typically is loaded with 165-grain bullets for deer hunting. While air-gun bullets are nearly three times as massive as those of conventional deer rifles, they are not nearly as fast. Bullets leave the muzzle of Ken’s Quackenbush rifle traveling at 750 fps. A .30-06 bullet zips along at nearly 2,800 fps, nearly four times the speed of Ken’s projectiles.

This has a couple of practical implications for air-gun hunters. First, they cannot shoot as far as hunters using conventional rifles. Bullets begin falling the moment they leave the muzzle, so a bullet traveling onequarter as fast as a modern rifle bullet drops four times as far in the time it takes to reach the target.

Partly because of bullet drop, Ken will not take shots at deer much beyond 50 yards. In contrast, a skilled marksman can easily shoot a deer at more than 200 yards with a .30-06. Pushing through air causes bullets to lose speed after leaving the muzzle. This reduces their ability to penetrate hide, flesh and bone, and is another reason why Ken hesitates to try shots beyond 50 yards.

Another avid air-gun deer hunter reduces this disadvantage by using lighter bullets. Nick Hammack, of Richland, loads his Quackenbush rifle with .45-cal. round lead balls weighing 143 grains. With the same air power behind them, these lighter bullets travel faster, making slightly longer shots practical. During the 2009 firearms deer season, Hammack shot a nine-point whitetail buck at 124 paces using a round ball. A longtime competitive shooter, Hammack understood his rifle’s capabilities well enough to know how much the lead ball would drop at the distance and compensate for it.

In spite of their limitations, air guns still are more than powerful enough for deer hunting. Hammack says he rarely recovers a bullet from a deer carcass. Most pass completely through the body.

Penetration is not the only measure of power, however. Bullets from center-fire rifles travel so fast that they generate shock waves when they strike living tissue. This “hydroshock” effect helps disable deer. Airrifle bullets travel much too slowly to create hydro-shock. Consequently, hunters must hit a deer’s lungs to cause a quick kill with air guns.

In this respect, air rifles have much more in common with crossbows than center-fire rifles. A double-lung shot with an arrow or a low-velocity bullet quickly shuts down a deer’s respiratory system, causing unconsciousness within seconds. Ken Cox said all six deer he and his son have shot fell within sight of their stands. Ken’s last kill, a nine-point buck, got just 20 yards before collapsing.

In some ways, air rifles’ low velocity is an asset. The modest power of large-caliber air rifles means virtually no recoil. This is not a big deal to the average hunter, but it could make the difference between hunting and not hunting for those with shoulder or spinal injuries.

Like arrows or shotgun slugs, bullets fired from air rifles do not travel far if they miss their targets. Some cities, like Wildwood, where the Coxes hunt, permit hunting with air rifles in the city limits to help reduce deer overpopulation and the attendant deer-vehicle accidents and property damage. Besides dramatically reducing the risk of line-of-fire accidents, air guns are much less noisy than conventional rifles.

The Quackenbush rifles Jeff and Ken use are 44 inches long and weigh 8 pounds, 6 ounces. That is longer and heavier than most conventional deer rifles, but comparable to traditional muzzleloaders. Like muzzleloaders, the Cox’s air-powered deer rifle can fire only one shot at a time, although reloading is easier. All they have to do is place another bullet in the breech and close it.

Missouri seems to be in the vanguard of air-gun hunting. Ken says he knows several out-of-state hunters who have started coming to Missouri to take advantage of a deer-hunting opportunity their states do not offer. I question whether air-gunning will ever be popular enough to provide a significant boost to the state’s economy, but we certainly can use help controlling suburban deer populations.

For the Coxes, the challenge of taking deer with an air rifle adds a new dimension to hunting.

“I have taken deer with highpowered rifles, muzzleloaders and archery equipment,” said Ken, “but the challenge and satisfaction of harvesting deer with a large bore air gun has me hooked!”

How it Works

Airguns work by using a burst of compressed air, rather than gunpowder, to force a projectile out of a barrel. Though spring-piston, pneumatic and CO2 types are available, only pneumatic air guns have been approved for deer hunting in Missouri. While a variety of configurations are possible, in this example, when the trigger is pulled, the spring-driven striker pushes the valve stem forward, opening the valves and allowing air from the precharged air reservoir to enter the system and press upward into the chamber, propelling the bullet out of the barrel.

Fire Power

Pneumatic guns use pre-compressed air from an external, high-compression power source. A special hose with a pressure gauge is used to siphon air from the source and into the air gun’s precharged air reservoir.

Air Gun History

Air-powered guns date back at least to the 16th century. In the late 18th and early 19th centuries, the Austrian army used .463- cal air guns capable of firing 22 shots on a charge. Lewis & Clark took an air rifle on their expedition in 1804-06 and amazed Indians with a rifle powerful enough to drive led balls into a tree trunk and capable of firing 40 shots from one charge. For more information about this rifle, see

Where Can I Get One?

If you would like to have an air rifle you will have to get in line. Demand for custom-made air rifles is big, and the supply is small.

Mass-produced versions are available. Search online for “large-caliber air rifle” to find suppliers. Expect to pay $600 or more for a new, factory-made air rifle suitable for deer hunting. This is in line with the cost of many of the better factory-made standard deer rifles.

Be Prepared

Before you begin any hunt, be sure you know the applicable regulations in the Wildlife Code and city ordinances. To view Wildlife Code regulations online, go to

This Issue's Staff

Editor In Chief - Ara Clark
Managing Editor - Nichole LeClair Terrill
Art Director - Cliff White
Writer/Editor - Tom Cwynar
Staff Writer - Bonnie Chasteen
Staff Writer - Jim Low
Photographer - Noppadol Paothong
Photographer - David Stonner
Designer - Stephanie Thurber
Artist - Dave Besenger
Artist - Mark Raithel
Circulation - Laura Scheuler