Shot (pellet)

Shot is a collective term for small spheres or pellets, often made of lead. These have been projected from slings since ancient times and were the original projectiles for shotguns and are still fired primarily from shotguns and grenade launchers, while they are less commonly used in riot guns. Shot shells are also available in many handgun calibers in a configuration known as "birdshot", "rat shot", or "snake shot".
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 Lead shot was originally made by pouring molten lead through screens into water, forming what was known as "swan shot", and, later, more economically mass-produced at higher quality using a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. 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.
The hardness of lead shot is controlled through adding variable amounts of tin, antimony and arsenic, forming alloys. This also affects its melting point. Hardness is also controlled by the rate of cooling that is used in manufacturing lead shot.
The , named after inventor Louis W. Bliemeister of Los Angeles, California, 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 into a hot liquid, where it is then rolled along an incline and then dropped another. The temperature of the liquid controls the cooling rate of the lead, while the surface tension of the liquid and the inclined surface 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 for #9 lead shot to about for #6 or #7 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 ranges, whereas soft lead shot, being softer and more likely to deform during firing, is preferred for improving shot pattern densities at very close 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 chokes.
The manufacture of non-lead shot differs from that of lead, with compression molding used to create some alloys.

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. 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 deer, moose, or caribou. Sizes range in ascending order from size #B to Tri-Ball. It is usually referred by the size, followed by "buck", e.g. "#000" is referred to as "triple-aught buck" in the United States or "triple-o buck" in other English speaking countries. Buckshot is traditionally swaged or cast. The Bliemeister method does not work for shot larger than #5, and works progressively poorly for shot sizes larger than about #6.

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.

U.S. Size	U.K. Size	Type	Mass	Pellets per oz	Pellets per oz	Diameter	Diameter
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	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		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	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