Buckshot
Larger sizes of shot, large enough that they must be carefully packed into the shell rather than simply dumped or poured in, are called "buckshot." Buckshot is used for hunting larger game, such as deer (hence derivation of the name), and also in riot shotguns and combat shotguns for defensive, police, and military use. Buckshot is also categorized by number, with smaller numbers being larger shot. It is called either "buckshot" or just "buck", such as "triple-ought buck" or "number 4 buck".
Size Nominal diameter Pellets/oz
TriBall (12 Ga.) <5> .60" (15.24 mm ) 3/4 ounce per pellet
0000 ("quadruple-ought") .38" (9.7 mm) 5
000 ("triple-ought") .36" (9.1 mm) 6
00 ("double-ought") .33" (8.4 mm) 8
0 ("ought") .32" (8.1 mm) 9
1 .30" (7.6 mm) 10
2 .27" (6.9 mm) 15
3 .25" (6.4 mm) 18
4 .24" (6 mm) 27