Pellet (air gun)

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A range of "diabolo" pellets with various nose profiles Air-gun-pellets.jpg
A range of "diabolo" pellets with various nose profiles

A pellet is a non-spherical projectile designed to be shot from an air gun, and an airgun that shoots such pellets is commonly known as a pellet gun. Air gun pellets differ from bullets and shot used in firearms in terms of the pressures encountered; airguns operate at pressures as low as 50 atmospheres, [1] while firearms operate at thousands of atmospheres. Airguns generally use a slightly undersized projectile that is designed to obturate upon shooting so as to seal the bore, and engage the rifling;[ citation needed ] firearms have sufficient pressure to force a slightly oversized bullet to fit the bore in order to form a tight seal. Since pellets may be shot through a smoothbore barrel, they are often designed to be inherently stable, much like the Foster slugs used in smoothbore shotguns.

Contents

Types

Diabolo pellet

Hornet Cal. 4,5mm (.177). Special pellet for hunting purposes. Lead with a point of brass. Extremely high penetrating power Hornet 45.jpg
Hornet Cal. 4,5mm (.177). Special pellet for hunting purposes. Lead with a point of brass. Extremely high penetrating power
Hunter Impact Cal. 4,5mm (.177). Pellet for hunting purposes. Lead with a point of synthetic polymers Hunter Impact 45.jpg
Hunter Impact Cal. 4,5mm (.177). Pellet for hunting purposes. Lead with a point of synthetic polymers

The diabolo pellet (or "wasp waist pellet") is the most common design traditionally found in airguns. It consists of a solid front portion called the head, which can have a flat ("wadcutter"), hemispherical ("round nose"), hollow point or conical ("pointed") front end profile, and a thin-walled funnel-shaped hollow rear portion called the skirt, joined by an hourglass-looking narrow mid-section known as the waist, giving the whole pellet the shape of a diabolo. The head is usually sized to just touch the rifling, and this keeps the pellet centered in the bore while keeping the friction as low as possible. The effect of friction is used in order to keep the pellet stationary until the piston has reached the end of its travel, compressing as much air as is possible.[ citation needed ] The thin hollow skirt is made of a malleable material, usually lead, although non-toxic alternatives are available that use tin or even plastic. During shooting, the skirt flares out and obturates the bore when pressure builds up behind it to provide a good seal that allows efficient pellet acceleration, and engages the rifling whereby imparting spin. In a smoothbore barrel, the skirt will still flare to provide a tight seal, but since there is no rifling the pellet will not spin, and is less accurate.

Because the majority of the pellet's mass resides in the solid head in the front, and the hollow skirt in the back generates significant drag during flight, this creates drag stability that will counteract yawing and help to maintain consistent trajectories. However, such stability is limited, and if the pellet's speed exceeds what the aerodynamics allow it will become unstable and start tumbling in flight. When this happens, the pellet can hit the target sideways and leave behind a keyhole-shaped impact hole on the target paper, instead of a clean round hole as expected from a direct frontal hit. This phenomenon is known as keyholing.

Pellets are designed to travel at subsonic speeds. High velocities can cause light pellets to overly deform, or even break apart in flight. The transition from subsonic to supersonic velocities will cause almost all pellets to tumble. The closer a pellet gets to the speed of sound, the more unstable it becomes. This is a problem for high-powered "magnum" break-barrel and pre-charged pneumatic air rifles, which are capable of pushing lighter pellets beyond the sound barrier. A few companies[ example needed ] have addressed this issue by manufacturing heavier-than-normal pellets for use in these high powered air guns.[ citation needed ] The heavier weight of these pellets ensures lower muzzle velocities, resulting in less chance of tumbling and more overall accuracy. Their weight also makes them sectionally denser and less susceptible to wind deviation and drag deceleration, and thus imparts better external and terminal ballistic performance.

Ball pellets

Steel ball shots with copper or zinc jackets BB copper and nickel plated.jpg
Steel ball shots with copper or zinc jackets

The earliest airgun pellets are actually small round lead shots similar to those used in muskets. First popularized by the Daisy BB Gun in the 1890s, a spring-piston airgun that shot "BB"-size birdshots, the .180-caliber lead shots were later replaced by the lighter .175-caliber steel shots modified from bearing balls, and remained popular as a plinking/pest shooting projectile due to the popularity and affordability of BB guns such as the Daisy Red Ryder.

Modern BB guns use the same calibers as the pellet guns, namely the .177 caliber and (occasionally) .22 caliber. Galvinized/copper-coated steel balls are the commonest projectile used in BB guns due to their better muzzle speed and penetration, but are only used in smoothbore barrels due to the risk of wearing down riflings, therefore lead balls are still used for rifled barrels.

Slug pellet

Eisenherz Cal. 4,5mm (.177). Plastic-coated pellet with a core of hard metal. For hunting purposes. Eisenherz 45.jpg
Eisenherz Cal. 4,5mm (.177). Plastic-coated pellet with a core of hard metal. For hunting purposes.
Plastic-coated pellets with a pointed steel core: Highest possible penetration power. Top: For rifles, bottom: for CO2-pistols with a revolver magazine Eisenherz long short.jpg
Plastic-coated pellets with a pointed steel core: Highest possible penetration power. Top: For rifles, bottom: for CO2-pistols with a revolver magazine

Recently, some manufacturers also have introduced the more cylindro-conoidally shaped "slug" pellets for some of the more powerful modern PCP air rifles. Contrasted to the commonly used diabolo pellets, these slug pellets resemble Minié balls, with cannelures and a hollow base, and have more contact surface with the bore and hence need greater propelling force to overcome friction, but they have better ballistic coefficients and thus longer effective ranges due to the more aerodynamic shape. Because these slug pellets have no skirts to generate enough drag stability in flight, they rely on spin stabilization from a fully rifled barrel.

Lead-free pellets

There are many different kinds of lead-free pellets, utilizing non-lead alloys and/or plastics in their construction. Consequently, they are much lighter than lead pellets, with weights ranging from 5.1 to around 20 grains. Due to their lighter weight, they accelerate more quickly inside the barrel, and commonly reach supersonic velocities. This increases the effective feet per second (FPS) of an airgun, which can result in greater accuracy.

However, lead-free pellets typically have a lower ballistic coefficient (BC), which results in more wind-drift, and reduced velocity at longer distances. As an example, H&N Sport's Baracuda Green pellet has a BC of 0.013, but the standard Baracuda pellet's BC is 0.024. [2]

Although some airguns are equipped with moderators or other noise dampening chambers, lead-free pellets can break the sound-barrier, and produce a loud cracking noise. This can be misinterpreted as a malfunction of the suppressor, when in fact it results from using a supersonic pellet. Upon switching back to a lead pellet, the supersonic crack will cease.

H&N Sport markets their lead-free pellets as part of their "GreenLine," and Gamo markets their lead-free pellets as a "Performance Ballistic Alloy" (PBA). Regardless of the terminology, the underlying technology involves a mix of non-lead materials, such as zinc, iron, tin, or copper. Lead-free pellets are offered by all major manufacturers, including RWS, Gamo, H&N Sport, Predator International, JSB, Crosman, Sig Sauer, and others. [3]

These metals are all lighter than lead, and significantly harder. As a result, they penetrate more deeply, and do not deform as greatly upon impact with the target. By contrast, lead pellets are often designed to fragment, expand, or mushroom, and can cause more damage. As a result, they are favored by hunters. However, many hunters are using non-lead pellets, to avoid lead contamination.

Match shooting use

A H&N Final Match Pistol 4.5 mm (.177 in) match diabolo pellet HundN FinaleMatchLP Front.jpg
A H&N Final Match Pistol 4.5 mm (.177 in) match diabolo pellet

Match pellets are used for the 10 metre air rifle and 10 metre air pistol disciplines. These 4.5 mm (0.177 in) calibre pellets have wadcutter heads, meaning the front is (nearly) flat, that leave clean, hole punch-like round holes in paper targets for easy scoring. Match pellets are offered in tins and more elaborate packagings that avoid deformation and other damage that could impair their uniformity.

Most match pellets are made of soft lead (a lead alloy with low antimony content), but some companies offer lead-free versions. The antimony content is used to control the hardness of the soft lead alloy. It is a very soft alloy, which makes it easy to process. Since the soft lead alloy is prone to strongly deform when striking a bullet catcher, it rapidly loses its kinetic energy and will not easily bounce off. Lead is toxic and hazardous to the environment, so precautions should be taken if shooting with lead pellets. For this reason, many shooters use lead-free match pellets, produced by H&N Sport, Predator International, JSB, RWS, Olympia Shot, Gamo, or Daisy.

Match air gun shooters are encouraged to perform shooting group tests with their gun clamped in a fixed rest in order to establish which particular pellet type performs best for their air gun. [4] [5] To facilitate maximum performance out of various air guns the leading match pellet manufacturers produce pellets in graduated weight variants (the light/high speed variants are often marketed for air pistol use) and with graduated "head sizes", which means the pellets are offered with front diameters from 4.48 mm (0.176 in) up to 4.52 mm (0.178 in).

However at higher and top competitive levels, even these variations are thought too coarse-grained and match pellets are batch tested; that is, the specific gun is mounted in a machine rest test rig and pellets from a specific production run on a specific machine with the same ingredients fed into the process (a batch) are test-fired through the gun. [6] Many different batches will be tested in this manner, and the pellets which give the smallest consistent group size without fliers (shots which fall outside of the main group) will be selected (small but inconsistent group sizes are not useful to a top competitor); and the shooter will then purchase several tens of thousands of pellets from that batch. Group sizes of 4.5 mm (0.177 in) diameter are theoretically possible, but practically shot groups of 5.0 mm (0.197 in) are considered highly competitive. [7] Unbatched ammunition, especially if the air gun is not regularly cleaned, is generally thought to be capable of only 8.0 mm (0.315 in) diameter group sizes. Batch testing match pellets for a particular gun is not generally thought to be worthwhile until the shooter reaches a high proficiency level, around the 95% level (570 for men, 380 for women).

See also

Related Research Articles

<span class="mw-page-title-main">Rifle</span> Common long range firearm

A rifle is a long-barreled firearm designed for accurate shooting and higher stopping power, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with both hands and braced firmly against the shooter's shoulder via a buttstock for stability during shooting. Rifles are used extensively in warfare, law enforcement, hunting and target shooting sports.

<span class="mw-page-title-main">Bullet</span> Projectile propelled by a firearm, sling, or air gun

A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constructions, including specialized functions such as hunting, target shooting, training, and combat. Bullets are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter in both imperial and metric measurement systems. Bullets do not normally contain explosives but strike or damage the intended target by transferring kinetic energy upon impact and penetration.

<span class="mw-page-title-main">Rifling</span> Grooves in a weapon barrel for accuracy

Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term for creating such grooves.

<span class="mw-page-title-main">Air gun</span> Gun that uses compressed air to launch projectiles

An air gun or airgun is a gun that uses energy from compressed air or other gases, which are mechanically pressurized and released as propellant for the chosen projectiles based on the principle of the primitive blowgun. This is in contrast to a firearm, which fires projectiles using energy generated through the burning of combustible propellants, most often gunpowder.

<span class="mw-page-title-main">.177 caliber</span> Pellet for air gun

.177 caliber or 4.5 mm caliber is the smallest diameter of pellets and BB shots widely used in air guns, and is the only caliber generally accepted for formal target competition. It is also sometimes used for hunting small game, like fowl. It is also used in field target competitions, where it competes with .20 caliber (5 mm) and .22 caliber (5.5 mm) rifles.

<span class="mw-page-title-main">Terminal ballistics</span> Projectiles behavior after reaching their targets

Terminal ballistics is a sub-field of ballistics concerned with the behavior and effects of a projectile when it hits and transfers its energy to a target.

<span class="mw-page-title-main">BB gun</span> Air gun that uses metallic ball projectiles called BBs

A BB gun is a type of air gun designed to shoot metallic spherical projectiles called BBs, which are approximately the same size as BB-size lead birdshot used in shotguns. Modern BB guns usually have a smoothbore barrel with a 4.5 mm (0.177 in) caliber, and use steel balls that measure 4.3–4.4 mm (0.171–0.173 in) in diameter and 0.33–0.35 g (5.1–5.4 gr) in weight, usually zinc- or copper-plated for corrosion resistance. Some manufacturers still make the slightly larger traditional lead balls that weigh around 0.48–0.50 g (7.4–7.7 gr), which are generally intended for use in rifled barrels.

<span class="mw-page-title-main">Wadcutter</span> Type of bullet

A wadcutter is a special-purpose flat-fronted bullet specifically designed for shooting paper targets, usually at close range and at subsonic velocities typically under approximately 270 metres per second (890 ft/s). Wadcutters have also found favor for use in self-defense guns, such as .38 caliber snubnosed revolvers, due to shorter barrel lengths, lower bullet velocities, and improved lethality. Wadcutters are often used in handgun and airgun competitions.

<span class="mw-page-title-main">Gun barrel</span> Firearm component which guides the projectile during acceleration

A gun barrel is a crucial part of gun-type weapons such as small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end (muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its caliber, usually measured in inches or millimetres.

<span class="mw-page-title-main">.22 Long Rifle</span> Common ammunition cartridge

The .22 Long Rifle or simply .22 LR or 22 is a long-established variety of .22 caliber rimfire ammunition originating from the United States. It is used in a wide range of rifles, pistols, revolvers, and submachine guns.

Internal ballistics, a subfield of ballistics, is the study of the propulsion of a projectile.

A slug is a term used for a bulky solid ballistic projectile. It is "solid" in the sense of being composed of one piece; the shape can vary widely, including partially hollowed shapes. The term is occasionally applied to bullets, but is most commonly applied to one-piece shotgun slugs, to differentiate them from shotshells containing numerous shots. Slugs are commonly fired from choked smoothbore barrels, but some specially-designed slug barrels have riflings that can impart gyroscopic spin required for in-flight stability.

<span class="mw-page-title-main">Shotgun shell</span> Self-contained cartridge loaded with either shot or a solid slug

A shotgun shell, shotshell, or shell is a type of rimmed, cylindrical (straight-walled) cartridges used specifically in shotguns, and is typically loaded with numerous small, pellet-like spherical sub-projectiles called shot, fired through a smoothbore barrel with a tapered constriction at the muzzle to regulate the extent of scattering. A shell can sometimes also contain only a single large solid projectile known as a slug. The hull usually consists of a paper or plastic tube often covered at the base by a metallic head cover which retains a primer, and the shot charge is typically contained by a wadding/sabot inside the case. The caliber of the shotshell is known as its gauge.

A pneumatic weapon is a weapon that fires a projectile by means of air pressure, similar in principle to the operation of pneumatic tube delivery systems. The term comes from a Greek word for "wind" or "breath" (πνεῦμα).

Obturation is the necessary barrel blockage or fit in a firearm or airgun created by a deformed soft projectile. A bullet or pellet made of soft material and often with a concave base will flare under the heat and pressure of firing, filling the bore and engaging the barrel's rifling. The mechanism by which an undersized soft-metal projectile enlarges to fill the barrel is, for hollow-base bullets, expansion from gas pressure within the base cavity and, for solid-base bullets, "upsetting"—the combined shortening and thickening that occurs when a malleable metal object is struck forcibly at one end.

<span class="mw-page-title-main">Daisy Outdoor Products</span> Air gun manufacturer

Daisy Outdoor Products is an American airgun manufacturer known particularly for their lines of BB guns. It was formed in 1882 initially as the Plymouth Iron Windmill Company in Plymouth, Michigan, to manufacture steel windmills, and from 1888 started bundling BB-caliber air guns with each windmill purchase as a sales promotion. With the unrivaled popularity of their 1888-model Daisy BB Guns, the company changed the name to Daisy Manufacturing Company in 1895 and switched their business to solely producing air guns for sale. Throughout the 20th century, Daisy has been known as a company that makes and sells BB guns and pellet youth rifles. Their Red Ryder BB Gun is perhaps the best known and longest production item, which has been featured in many TV shows and movies since its introduction in the spring of 1940.

<span class="mw-page-title-main">Airsoft pellets</span>

Airsoft pellets (known as BBs) are spherical projectiles used by airsoft guns. Typically made of plastic, they usually measure around 6 mm (0.24 in) in diameter (though selective models use 8 mm), and weigh 0.20–0.40 g (3.1–6.2 gr), with the most common weights being 0.20 g and 0.25 g, while 0.28 g, 0.30 g, 0.32g and 0.40g BBs are also commonplace. Though frequently referred to as "BBs" among airsoft users, these BBs are not the same as either of the 4.5 mm metal projectiles that BB guns fire, or the 4.6 mm (0.180 in)-sized birdshot from which the term "BB" originated.

<span class="mw-page-title-main">Crosman 1377</span> Air pistol

The Crosman model 1377 is a single-shot, bolt-action, pneumatic .177 caliber pellet gun, featuring a rifled steel barrel and imitation wood checkered plastic grips. The 1377 was introduced in 1977, and has been in continuous production ever since. A separately available shoulder stock converts the rather long pistol into a carbine. The 1377 is not a competition level target airgun, but its long-rifled barrel makes it fairly accurate.

<span class="mw-page-title-main">Crosman 2100 Classic</span> Pneumatic Air Rifle

The Crosman 2100B is an American-made pneumatic air gun that is manufactured for small game hunting, large and small pest control, and target shooting.

<span class="mw-page-title-main">Crosman 1322</span> Air pistol

The Crosman model 1322Medalist .22 Caliber Pellet Air Pistol was a single-shot, bolt-action loading, pneumatic pump-action .22-caliber air pistol, featuring a button-rifled 10.1-in. (256 mm) steel barrel and checkered plastic grips. The 1322 was introduced in 1977 by Crosman as a general-purpose air pistol for target practice and small game hunting. It was in production, in three separate manufacturing versions, until 2004, when it was discontinued from sale in the U.S.A. In 2012 the gun has been reintroduced by Crosman.

References

  1. House, Jim. "HUNTING WITH AIRGUNS Ch.6". crosman.com. Crosman. Archived from the original on 14 December 2014. Retrieved 10 December 2014.
  2. "Compare products | H&N Sport". www.hn-sport.de. Retrieved 2022-05-02.
  3. "Home - Lead Free Pellets". www.leadfreepellets.org. Retrieved 2022-05-02.
  4. "About Pellet Numbers and Pellet Testing". Vogel USA. Archived from the original on 2012-05-04. Retrieved 2012-05-01.
  5. Air Gun Testing Target Pellets
  6. Scott Pilkington (May–June 2008). "About Pellet Numbers and Pellet Testing" (PDF). USA Shooting News. Retrieved 2013-02-20.
  7. Haendler & Natermann Finale Match Rifle

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