Most of the major ammunition catalogs, specifically including those published by Federal, Remington and Winchester, as well as a number of books about arms and ammunition, publish general information about steel and lead shot and make recommendations concerning the appropriate shot sizes for various purposes.

Perhaps it might be worthwhile to start by listing the nominal diameter of the various common sizes of shot as manufactured in the U.S. Here they are, courtesy of the Federal Ammunition Catalog:

BBB .190" (4.83mm), BB .180" (4.57mm), 1 .160" (4.06mm), 2 .150" (3.81mm), 3 .140" (3.56mm), 4 .130" (3.30mm), 5 .120" (3.05mm), 6 .110" (2.79mm), 7 .100" (2.41mm), 7-1/2 .095" (2.35mm), 8 .090" (2.29mm), 8-1/2 .085" (2.16mm), 9 .080" (2.03mm).

Here is the average pellet count in one ounce (28.35 grams) of 3% antimony, 97% lead shot of various selected sizes, courtesy of the Winchester Ammunition 2004 Product Guide:

BB - 50, 2 - 87, 4 - 135, 5 - 170, 6 - 225, 7-1/2 - 350, 8 - 410, 8-1/2 - 497, 9 - 585.

Here is the average pellet count in one ounce of steel shot of various selected sizes, also courtesy of the Winchester Ammunition 2004 Product Guide:

BBB - 62, BB - 72, 1 - 103, 2 - 125, 3 - 158, 4 - 192, 5 - 243, 6 - 315.

Lead shot is superior ballistically, hits harder, penetrates deeper, breaks targets more decisively and kills better than steel shot. It is also easier on your gun barrel. Always use lead shot (or tungsten alloy shot, which is ballistically similar) whenever possible.

Here are some shot size recommendations based on my personal experience and research, supplanted by and cross-checked against the information presented by the big loading companies. This was done to insure that these suggestions would not lead the readers of Guns and Shooting Online astray.

For most shooting there is a limited range of shot sizes that are acceptable. Keep in mind that when shooting any given type of game at shorter range the smaller shot sizes are generally preferred, and at longer ranges the larger shot sizes are usually preferable.

Also, in order to maintain adequate pattern density, the largest shot sizes (BBB to #2) should generally be reserved for use in the large bore (10 and 12 gauge) guns. 16 and 20 gauge guns are generally best used with lead shot no larger than #4 even in the heaviest magnum loads, and #6 or smaller shot will give denser patterns in standard shells. The small bore 28 gauge is probably best used with shot no larger than #6, and I can see no point to using shot larger than #7-1/2 in .410 bore guns.

• 16 yard Trap - 8, 8-1/2
• Handicap Trap - 7-1/2, 8
• Skeet - 9
• Sporting Clays - 7-1/2, 8, 8-1/2
• Live Pigeon - 7-1/2

• Turkey - 4, 5, 6
• Pheasant - 5
• Chukker, Grouse, and Partridge - 6, 7-1/2
• Quail - 7-1/2, 8
• Dove - 7-1/2
• Rail, Snipe and Woodcock - 7-1/2, 8
• Rabbit - 6, 7-1/2
• Squirrel - 6

• Geese - BBB, BB, 1
• Ducks (over decoys) - 2, 3, 4
• Ducks (pass shooting) - BB, 1, 2

• Geese - BB, 2
• Ducks (over decoys) - 4, 5, 6
• Ducks (pass shooting) - 2, 4

One last note: it is a very good idea to pattern your shotgun with whatever load you have selected before you go hunting. I know it is a lot of trouble, but shooting a few test patterns can prevent a lot of grief. Few shotguns shoot all shot sizes equally well, and sometimes going up or down just a single shot size can make a dramatic difference in pattern distribution. Ignorance is not bliss; know before you go.