Shot (pellet)
Shot is a
Lead shot is also used for a variety of other purposes such as filling cavities with dense material for weight and/or balance. Some versions may be plated with other metals. Lead shot was originally made by pouring molten lead through screens into water, forming what was known as "swan shot", and, later, more economically mass-produced at higher quality using a shot tower. The Bliemeister method has supplanted the shot tower method since the early 1960s.
Manufacture
Producing lead shot from a shot tower was pioneered in the late 18th century by William Watts of Bristol who adapted his house on Redcliffe Hill by adding a three-storey tower and digging a shaft under the house through the caves underneath to achieve the required drop. The process was patented in 1782.[1] The process was later brought above ground through the building of shot towers.
Molten lead would be dropped from the top of the tower. Like most liquids, surface tension makes drops of molten lead become near-spherical as they fall. When the tower is high enough, the lead droplets will solidify during the fall and thus retain their spherical form. Water is usually placed at the bottom of the tower, cooling the lead immediately upon landing.
Roundness of manufactured shot produced from the shot tower process is graded by forcing the newly produced shot to roll accurately down inclined planes. Unround shot will naturally roll to the side, for collection. The unround shot was either re-processed in another attempt to make round shot using the shot tower again, or used for applications which did not require round shot (e.g., split shot for fishing).[1]
The hardness of lead shot is controlled through adding variable amounts of tin, antimony and arsenic, forming alloys.[1] This also affects its melting point. Hardness is also controlled by the rate of cooling that is used in manufacturing lead shot.
The Bliemeister method, named after inventor Louis W. Bliemeister of Los Angeles, California, (U.S. patent 2,978,742, dated April 11, 1961) is a process for making lead shot in small sizes from about #7 to about #9. In this process, molten lead is dripped from small orifices and dropped approximately 1 inch (2.5 cm) into a hot liquid, where it is then rolled along an incline and then dropped another 3 feet (90 cm). The temperature of the liquid controls the cooling rate of the lead, while the surface tension of the liquid and the inclined surface(s) work together to bring the small droplets of lead into highly regular balls of lead in spherical form. The size of the lead shot that is produced is determined by the diameter of the orifice used to drip the lead, ranging from approximately 0.018 inches (0.46 mm) for #9 lead shot to about 0.025 inches (0.64 mm) for #6 or #7.0 shot, while also depending on the specific lead alloy that is used.
The roundness of the lead shot depends on the angle of the inclined surfaces as well as the temperature of the liquid coolant. Various coolants have successfully been used, ranging from diesel fuel to antifreeze and water-soluble oil. After the lead shot cools, it is washed, then dried, and small amounts of graphite are finally added to prevent clumping of the lead shot. Lead shot larger than about #5 tends to clump badly when fed through tubes, even when graphite is used, whereas lead shot smaller than about #6 tends not to clump when fed through tubes when graphite is used.
Lead shot dropped quickly into liquid cooling baths when being produced from molten lead is known as "chilled lead shot", in contrast to "soft lead shot" which is produced by molten lead not being dropped as quickly into a liquid cooling bath. The process of rapidly chilling lead shot during its manufacturing process causes the shot to become harder than it would otherwise be if allowed to cool more slowly. Hence, chilled lead shot, being harder and less likely to deform during firing, is preferred by shotgunners for improving shot pattern densities at longer (> 30 yards (27 m)) ranges, whereas soft lead shot, being softer and more likely to deform during firing, is preferred for improving shot pattern densities at very close (< 20 yards (18 m)) ranges as the softer and now deformed shot scatters more quickly when fired. Soft lead shot is also more readily deformed during the firing process by the effects of chokes.
The manufacture of non-lead shot differs from that of lead, with compression molding used to create some alloys.[2]
Sizes
Shot is available in many sizes for different applications. The size of numbered shot decreases as the number increases. In hunting, some sizes are traditionally used for certain game, or certain shooting situations, although there is overlap and subjective preference. The range at which game is typically encountered and the penetration needed to assure a clean kill must both be considered. Local hunting regulations may also specify a size range for certain game. Shot loses its velocity very quickly due to its low sectional density and ballistic coefficient (see external ballistics). Generally, larger shot carries farther, and does not spread out as much as smaller shot.
Buckshot
Buckshot is a shot formed to larger diameters so that it can be used against bigger game such as
Lead shot comparison chart
Below is a chart with diameters per pellet and weight for idealized lead spheres for U.S. Standard Designations with a comparison to English shot sizes.[3][4]
U.S. Size | U.K. Size | Type | Mass (grains) | Pellets per
oz (lead) |
Pellets per
oz (steel) |
Diameter (in) | Diameter (mm) |
---|---|---|---|---|---|---|---|
0000 | Buck | 82 | 0.38 | 9.65 | |||
000½ | Buck | 76 | 0.37 | 9.4 | |||
000 | LG | Buck | 70 | 6 | n/a | 0.36 | 9.14 |
MG (mould) | Buck | 62.5 | 7 | n/a | 0.347 | 8.81 | |
00½ | Buck | 59 | 0.34 | 8.64 | |||
SG | Buck | 54.7 | 8 | n/a | 0.332 | 8.43 | |
00 | Buck | 53.8 | 8 | 0.33 | 8.38 | ||
0 | Buck | 49 | 9 | 0.32 | 8.13 | ||
#1½ | Buck | 44.7 | 0.31 | 7.87 | |||
#1 | Buck | 40.5 | 10 | 0.30 | 7.62 | ||
Special SG | Buck | 39.8 | 11 | n/a | 0.298 | 7.57 | |
#2½ | Buck | 36.6 | 0.29 | 7.37 | |||
#2 | Buck | 29.4 | 14 | 0.27 | 6.86 | ||
SSG | Buck | 29.17 | 15 | n/a | 0.269 | 6.83 | |
#3½ | Buck | 26.3 | 0.26 | 6.6 | |||
#3 | Buck | 23.4 | 18 | 0.25 | 6.35 | ||
SSSG | Buck | 21.89 | 20 | n/a | 0.245 | 6.22 | |
#4 | Buck | 20.7 | 21 | 0.24 | 6.1 | ||
FF | Waterfowl | 18.2 | 0.23 | 5.84 | |||
SSSSG | Buck | 17.50 | 25 | n/a | 0.227 | 5.77 | |
F (or TTT) | Waterfowl | 16.0 | 0.22 | 5.59 | |||
SSSSSG
or AAAA |
Buck/
Waterfowl |
14.58 | 30 | n/a | 0.214 | 5.44 | |
TT | Waterfowl | 13.9 | 0.21 | 5.33 | |||
AAA | Waterfowl | 12.5 | 35 | n/a | 0.203 | 5.16 | |
T | Waterfowl | 12.0 | n/a | 53 | 0.20 | 5.08 | |
AA | Waterfowl | 10.94 | 40 | n/a | 0.194 | 4.93 | |
BBB | Waterfowl | 10.2 | n/a | 61 | 0.19 | 4.83 | |
BB | A or BBBB | Waterfowl | 8.75 | 50 | 72 | 0.18 | 4.57 |
B | BBB | Waterfowl | 7.29 – 7.40 | 60 | 86 | 0.17 | 4.32 |
BB | Waterfowl | 6.25 | 70 | n/a | 0.161 | 4.09 | |
#1 | B | Waterfowl | 5.47 | 80 | 103 | 0.154 | 3.91 |
#2 | Waterfowl | 4.86 | 90 | 125 | 0.15 | 3.81 | |
#1 | Waterfowl | 4.38 | 100 | n/a | 0.143 | 3.63 | |
#3 | #2 | Waterfowl | 3.65 | 120 | 154 | 0.135 | 3.43 – 3.56 |
#4 | Waterfowl | 3.24 | 135 | 192 | 0.13 | 3.3 | |
#3 | Waterfowl | 3.12 | 140 | n/a | 0.128 | 3.25 | |
#4½ | Bird | 2.90 | 0.125 | 3.18 | |||
#5 | #4 | Bird | 2.57 | 170 | 243 | 0.12 | 3.05 |
#4½ | Bird | 2.19 | 200 | n/a | 0.113 | 2.87 | |
#6 | #5 | Bird | 1.94 – 1.99 | 220 – 225 | 317 | 0.11 | 2.79 |
#5½ (m.g.) | Bird | 1.82 | 240 | n/a | 0.107 | 2.72 | |
#6 | Bird | 1.62 | 270 | n/a | 0.102 | 2.59 | |
#7 | #6½ | Bird | 1.458 | 300 | 420 | 0.10 | 2.54 |
#7 | Bird/Clay | 1.29 | 340 | n/a | 0.095 | 2.41 | |
#7½ | Bird/Clay | 1.25 | 350 | 490 | 0.095 | 2.413 | |
#8 | Bird/Clay | 1.067 | 410 | 577 | 0.09 | 2.286 | |
#8½ | #8 | Bird/Clay | 0.97 | 450 | n/a | 0.085 – 0.087 | 2.16 – 2.21 |
#9 | #9 | Bird/Clay | 0.748 | 580 – 585 | n/a | 0.08 | 2.032 |
#9½ | Bird/Clay | 0.63 | 0.075 | 1.91 | |||
#10 | #10 | Pest | 0.51 | 850 | n/a | 0.07 | 1.78 |
#11 | Pest | 0.42 | 1,040 | n/a | 0.066 | 1.68 | |
#12 | Pest | 0.35 | 1,250 | n/a | 0.062 | 1.57 | |
#11 | Pest | 0.32 | 0.06 | 1.52 | |||
#12 | Pest | 0.183 | 2,385 | n/a | 0.05 | 1.27 | |
Dust | Pest | 0.17 | 2,600 | n/a | 0.048 | 1.22 | |
Dust | Pest | 0.10 or less | 0.04 | 1.02 |
Applications outside firearms
When used as a pourable/mouldable weight, lead shot may be left loose, or mixed with a bonding agent such as epoxy to contain and stabilize the pellets after they are poured.
Some applications of lead shot are:
- As ballast in various situations, especially where a dense, pourable weight is required. Generally, small shot is best for these applications, as it can be poured more like a liquid. Completely round shot is not required.
- Stress testing: Providing variable weights in strength-of-materials stress-testing systems. Shot pours from a hopper into a basket, which is connected to the test item. When the test item fractures, the chute closes and the mass of the lead shot in the basket is used to calculate the fracture stress of the item.
- Hydrometers: use a weight made of shot, since the weight has to be poured into a narrow glass vessel.
- Split shot, a larger type of lead shot where each pellet is cut part-way through the diameter. This type of shot was formerly commonly used as a line weight in angling. They are no longer solely manufactured from lead but instead are often made from softer materials that can be easily pressed onto the fishing line instead of being closed in a crimp using pliers, as was once common.
- The heads of some dead blow hammersare filled with shot to minimize rebound off the struck surface.
- weight beltscontain pouches filled with lead shot.
- Many blackjacks and saps use lead shot as a flexible weight to deliver high energy blows while minimizing damage from sharp impact force (similar to the way it is used in dead blow hammers).
- Loudspeaker stands can be filled with lead shot for additional acoustic decoupling, as well as stability.
- Model rocketry: to add weight to the nose of the rocket, increasing the stability factor.
- Due to its heat capacitycryocoolers.
- Due to lead's high density, it is used to attenuate radiation shielding.
Bird lead poisoning
The examples and perspective in this section deal primarily with the United States and do not represent a worldwide view of the subject. (November 2021) |
Lead shot-related waterfowl
Lead from spent ammunition also impacts scavenging bird species such as vultures, ravens, eagles and other birds of prey. Foraging studies of the endangered
Restrictions on the use of lead
Depending on hunting laws, alternatives to lead shot are mandated for use by hunters in certain locations or when hunting migratory waterfowl and migratory birds or when hunting within U.S. federal waterfowl production areas, U.S. national wildlife refuges, or some state wildlife management areas. Lead shot is also banned within an eight-county area in California designated as the condor's range. As of 2011, thirty-five states prohibited lead shot use in such specially-specified areas when hunting. While hunting non-migratory or upland birds, as well as animals, in the United States, lead shot is generally approved, except within the specially-designated non-toxic shot pellet zones.[13]
In an effort to protect the condor, the use of projectiles containing lead has been banned for hunting wild boar, deer, antelope, elk, pronghorn, antelope, coyote, squirrel, and other non-game wildlife in areas of California designated as its habitat range.[14] The bald eagle has similarly been shown to be affected by lead originating from dead or wounded waterfowl—the requirement to protect this species was one of the biggest factors behind laws being introduced in 1991 by the United States Fish and Wildlife Service to ban lead shot in migratory waterfowl hunting.[15]
Hunting restrictions have also banned the use of lead shot while hunting migratory waterfowl in at least 29 countries across by international agreement,
The Missouri Department of Conservation introduced regulations in 2007 in some hunting areas requiring the use of non-toxic shot to protect upland birds.[11] Some clay pigeon ranges in the US have banned the use of lead after elevated levels of lead were found in waterfowl, small birds, mammals and frogs in their vicinity.[11]
Non-toxic alternatives to lead shot
Approved alternatives while hunting migratory waterfowl include pellets manufactured from
Steel was one of the first widely used lead alternatives that the ammunition industry turned to.[19] But steel is one hundred times harder than lead, with only two-thirds its density, resulting in undesirable ballistic properties compared to lead.[20] Steel shot can be as hard as some barrels, and may therefore damage chokes on older firearms that were designed only for use with softer lead shot.[19] The higher pressures required to compensate for the lower density of steel may exceed the design limits of a barrel.
Within recent years, several companies have created non-toxic shot out of
Approved shot type | Percent composition by weight |
---|---|
Bismuth-tin | 97% bismuth, and 3% tin |
Iron (steel) | Iron and carbon |
Iron-tungsten | Any proportion of tungsten, and >1% iron |
Iron-tungsten-nickel | >1% iron, any proportion of tungsten, and up to 40% nickel |
Tungsten-bronze | 51.1% tungsten, 44.4% copper, 3.9% tin, and 0.6% iron, or 60% tungsten, 35.1% copper, 3.9% tin, and 1% iron |
Tungsten-iron-copper-nickel | 40–76% tungsten, 10–37% iron, 9–16% copper, and 5–7% nickel |
Tungsten-matrix | 95.9% tungsten, 4.1% polymer |
Tungsten-polymer | 95.5% tungsten, 4.5% Nylon 6 or Nylon 11 |
Tungsten-tin-iron | Any proportions of tungsten and tin, and >1% iron |
Tungsten-tin-bismuth | Any proportions of tungsten, tin, and bismuth. |
Tungsten-tin-iron-nickel | 65% tungsten, 21.8% tin, 10.4% iron, and 2.8% nickel |
Tungsten-iron-polymer | 41.5–95.2% tungsten, 1.5–52.0% iron, and 3.5–8.0% fluoropolymer |
See also
References
- ^ ISBN 978-0-8247-8247-4.
- ISBN 978-1440226915.
- ^ "Shotgun Shell Shot Size Comparison Chart Actual size". Retrieved 2022-05-24.
- ^ "English Shot sizes". Vintage Guns. Retrieved 2022-05-24.
- ^ According to Dulong–Petit law heat capacity of metals is coursely proportional to mass.
- S2CID 21280606.
- ^ Federal Cartridge Company Waterfowl and Steel Shot Guide. Volume I; 1988.
- ^ Sanderson, Glen C. and Frank C. Bellrose. 1986. A Review of the Problem of Lead Poisoning in Waterfowl. Illinois Natural History Survey, Champaign, Illinois. Special Publication 4. 34pp. full report from scholar.google.com (cache)
- ^ A.M. Scheuhammer and S. L. Norris. 1996. "The ecotoxicology of lead shot and lead fishing weights" Ecotoxicology Vol. 5 Number 5 pp. 279-295
- ^ AEWA. 5 Nov 2009. p. 3. Retrieved 17 November 2020.
- ^ a b c d Lahner, Lesanna L.; Franson, J. Christian. "Lead Poisoning in Wild Birds" (PDF). USGS National Wildlife Health Center. p. 2. Retrieved 4 Apr 2013.
- ^ PMID 19107211.
- ^ Elizabeth Weise & Adam Belz (2011-08-23). "Iowa in middle of lead-shot skirmish". USA Today. Retrieved 3 Apr 2011.
- ^ "Get the Lead Out (Protecting the Condor)". California Department of Fish and Game. Archived from the original on 30 July 2009. Retrieved 2009-07-28.
- ^ ISBN 978-0387894324.
- ^ "Protecting Waterfowl From Lead In Wetlands: A Practical Guide to the Lead Shot Regulations in Northern Ireland" (PDF). Ireland: Countryside Alliance. 24 Apr 2009. Archived from the original (PDF) on 2013-02-27. Retrieved 24 Mar 2013.
- ISBN 978-9287130709.
- ISBN 978-0521577830.
- ^ ISBN 978-1440213304.
- ^ "Lead Poisoning in Waterbirds: Alternatives to Lead Shot". AEWA. Retrieved 25 Mar 2013.
- US Fish and Wildlife Service. 4 Apr 2013. Retrieved 4 Apr 2013.