Lead shot
Lead shot is a collective term for small balls of lead. These were the original projectiles for muskets and early rifles, but today shot is fired primarily from shotguns. It is also used for a variety of other purposes. It was originally made by pouring molten lead into wooden molds and later more economically mass-produced using a shot tower.
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[edit] Manufacturing
Lead shot was pioneered by William Watts of Bristol who adapted his house on Redcliff Way by adding a three story tower and digging a shaft under the house through the caves underneath to achieve the required drop. The process was patented in 1782.
The process was brought above ground through the building of shot towers. Molten lead would be dropped from the top of the tower. Like most liquids, molten lead becomes spherical as it falls. Water is usually placed at the bottom of the tower, causing the lead to be cooled immediately after dropping.
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 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).
Hardness of lead shot for shotgun shells is controlled through adding variable amounts of antimony, forming lead-antimony alloys.
The Bliemeister method, named for Louis Bliemeister, the man who patented it, is a process for making lead shot in small sizes which has largely supplanted the shot tower method. In this process, metered molten lead is dropped approximately 1 in (25 mm) into hot water, rolled along an incline and then dropped another 3 ft (0.91 m). The water temperature controls the cooling rate of the lead, while the surface tension brings the ball into a spherical form. Antimony, added for hardness, also lowers the melting point of lead.
[edit] Sizes
- Main article: shotgun shell
Larger lead shot comes in three sizes: B, BB, and BBB. Smaller lead shot is available in shot in sizes 7½, 8, and 9, with applications ranging from sporting clays and skeet shooting, to non-waterfowl hunting at progressively shorter distances. The larger bird shot sizes (i.e., 6, 5, 4) are more difficult to obtain in lead, having been banned for waterfowl hunting since the 1970s in the United States, although they are still occasionally seen, and remain legal for uses other than for waterfowl hunting. Older shotguns continue to use lead shot, as firing newer, harder, non-lead shot may damage the shotgun, and firing soft metal substitutes for lead shot may not be economically-viable.
[edit] Buckshot
Buckshot is simply lead shot formed to larger diameters. Sizes range in ascending order from size B to size 0000.
[edit] Comparison Chart
Below is a chart with diameters per pellet and weight for idealized lead spheres.
| Size | Type | weight | diameter |
|---|---|---|---|
| #0000 | Buck | 5.51 g (85 gr.) | 9.40 mm (0.380") |
| #000 | Buck | 4.54 g (70 gr.) | 9.14 mm (0.360") |
| #00 | Buck | 3.49 g (53.8 gr.) | 8.38 mm (0.330") |
| #0 | Buck | 3.18 g (49 gr.) | 8.13 mm (0.320") |
| #1 | Buck | 2.62 g (40.5 gr.) | 7.62 mm (0.300") |
| #2 | Buck | 1.91 g (29.4 gr.) | 6.86 mm (0.270") |
| #3 | Buck | 1.52 g (23.4 gr.) | 6.35 mm (0.250") |
| #4 | Buck | 1.34 g (20.7 gr.) | 6.09 mm (0.240") |
| #FF | Buck | 1.18 g (18.2 gr.) | 5.84 mm (0.230") |
| #F (TTT) | Buck | 1.05 g (16.2 gr.) | 5.59 mm (0.220") |
| #TT | Buck | 0.98 g (15.1 gr.) | 5.33 mm (0.210") |
| #T | Buck | 0.89 g (13.7 gr.) | 5.08 mm (0.200") |
| #BBB | 0.66 g (10.2 gr.) | 4.82 mm (0.190") | |
| #BB | 0.57 g (8.8 gr.) | 4.57 mm (0.180") | |
| #B | 0.48 g (7.4 gr.) | 4.32 mm (0.170") |
[edit] Non-firearm uses
Lead shot is also often used 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. Examples are:-
- 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 also often use a weight made of shot, since the weight has to be poured into a narrow glass vessel.
- Split shot is a larger type of lead shot where each pellet is cut part-way through the diameter, and has been commonly used as a line weight in angling. Split shot is placed over the line and closed in a crimp using pliers in this application.
- The heads of some dead blow hammers are filled with shot to minimize rebound off the struck surface.
- Some scuba diving weight belts are nylon webbing pouches filled with shot.
- It can be used to fill speaker stands for additional acoustic decoupling, as well as stability.
[edit] Non lead alternatives
When hunters use lead shot, waterfowl such as ducks can ingest the spent pellets later and be poisoned; predators that eat these birds are also at risk. There are various places in the world (e.g. Wetlands in Britain) where hunting using lead shot is banned due to the toxic nature of the lead. For these situations, non lead alternatives have been introduced, using materials such as steel, tungsten-nickel-iron, bismuth-tin, and tungsten-polymer.
