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BB gun

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BB guns are guns that fire small bore projectiles called BBs. Most BB guns are incapable of causing significant harm to humans or large animals unless they are successfully aimed at particularly sensitive body parts. The primary use of these guns is for target shooting, and sometimes for the hunting of small animals. BB guns are restricted by law in some countries. "BB" is derived from "ball bearing", as early BB ammunition often came from ball bearing manufacturers. It is often misinterpreted as "Baby Bullet".

Contents

Operation

BB guns that are powered by a previously compressed gas can utilize either one-time-use canisters (the most common being the 12 gram CO2 Cartridge), or refillable canisters, to propel the projectile through the barrel. With CO2 cartridges, pressure drops as gas is expelled with each shot, thus CO2 cartridges need to be changed often as pressure available drops too low. A compressed gas BB gun usually has a revolver style loading mechanism that rotates after every shot, or, in the case of some BB pistols, a spring magazine that is loaded into the pistol grip. Previously compressed gases can propel BBs up to 800 ft/s (240 m/s).

BB guns can also utilize hand pumps that allow for air from the atmosphere to be compressed and utilized in a similar manner to previously compressed gases. The disadvantage that a hand-pumped gun has is that it takes more time to reload, as opposed to previously compressed gas BB guns, which are usually semi-automatic. The slow rate of fire is offset by the decreased cost of operating, reliability, non-reliance on the availability of CO2 cartridges. This type of gun typically uses a bolt action type loading mechanism, similar to bolt action rifles, where a BB can be pulled by a magnetic (usually) breech block from an internal reservoir or a lead pellet hand loaded into an open groove in the gun. These guns usually have a projectile velocity between 100 to 750 ft/s (30 to 230 m/s).

In addition to hand-pumped and compressed gas guns, there are also two types of spring BB gun; spring piston and spring rod.

A spring rod propulsion system consists of a rod attached to a spring. When the gun is cocked, the rod is pulled back, and a bb is loaded. When the gun is fired, the compressed spring pushes the rod a short length down the barrel at high speed, thus propelling the BB down the barrel. The loading mechanism is usually internal and doesn't allow for pellets. Spring rod BB guns are generally inexpensive and marketed to children as a "first BB gun" since they have lower projectile velocities, around 175 ft/s (50 m/s).

The spring piston type uses a compression spring, like spring rod guns, but instead is attached to a plunger in a pressure chamber many times the diameter of the barrel, allowing the gases to be propelled much faster in the barrel than the spring itself. This type of BB gun, when a rifle, is usually a single-shot breechloader with a break barrel, which cocks the gun when pulled down and can send a BB up to 1000 ft/s (300 m/s). A spring piston BB rifle is famous for its consistency and is often used in competitive target shooting and as varmint rifles. As a pistol a spring piston can utilize either a BB magazine or a breech which allows for pellets. Spring piston pistols usually achieve a velocity of 300 ft/s (90 m/s).

Two well-known American manufacturers of BB guns are Crosman Corporation and Daisy Outdoor Products.

Although progress has been made since the Lewis and Clark airgun, the power per shot has severely declined. This is because manufacturers have made sure that the valve does not open like they used to. Because of this, more shots can be fired, but they are all less powerful.

Ammunition

The name of the gun refers to the original ammunition it used, which came from the lead shot used in a shotgun shell. "BB" (0.18 inch) was the size between "B" and "BBB". Modern rounds are made of non-toxic steel, plastic, or copper, and are usually .177 caliber (4.5 mm). BB is derived from "ball bearing", as early BB ammunition often came from ball bearing manufacturers. It is often misinterpreted as "Baby Bullet".

BBs are not the only type of ammunition used in air guns. Some air guns also use shaped pieces of lead called pellets. These vary widely in shape, but generally have a hollow, flared back end intended to engage the rifling in the barrel, which spins the pellets and gives them stability in flight.

Another type of ammunition used in smooth bore air guns is the dart, which looks like a small nail with a tassel on the end. Darts are used only in low-powered guns for indoor target practice, and can be used in place of hand-thrown darts in a game of darts. The original air gun darts were used in very accurate, handmade, target guns used in formal competition in late 19th and early 20th Century Germany.

Restricted air guns

A Firearms Certificate (FAC) is a certificate issued in the United Kingdom for a rifle capable of shooting a pellet that leaves the muzzle with a muzzle energy of over 12 ft·lbf (16.3 joules). 12 ft·lbf is the maximum energy level permitted in the UK without an FAC certificate. Other countries may have a different energy transfer limit; the United States does not have a limit.

However, air guns can be deceptively powerful. A Shin Sung Career .50 cal Big Bore rifle—one of the most powerful air guns made today—is capable of propelling a 225 grain (14.6 g) lead pellet at 584 ft/s (178 m/s) with a muzzle energy of 229 ft·lbf (310 J). A modern military handgun using 9 mm Luger ammunition is capable of propelling a 115 grain (7.5 g) copper jacketed lead bullet at 1150 ft/s (350 m/s) with a muzzle energy of 336 ft·lbf (456 J). BB-type ammunition can be powerful enough to be used in riot control and other law enforcement. Army and police forces use various air guns such as FN 303.

Additionally, some owners modify their BB guns for higher muzzle energy. By doing so, they increase the power per shot of the rifle. Modifications can include:

However, as this increases the power of the rifle, the gun can cross the country's legal limit and turn it into an illegal firearm (if the owner does not have an FAC).

See also

External links

 

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