These are the basics of understanding Bird Shot for upland game.
To give a brief background on bird shot and what shot size means before we get into what cartridge for what game lets talk what the number mean. The larger the number (#8 for example) the more pellets in the shell which translates into smaller pellets. The smaller the pellets or shot size the faster the pellets will spread out. Creating a wider pattern at a shorter range and reducing long range effectiveness.
Although there are a wide array of types of materials that now go into shot shells we will talk about the two most popular. The first being lead shot which is the most common for upland bird hunting and turkey hunting. Then there is steel shot which is required by federal law to be used when hunting Waterfowl do to the toxicity of lead in water. there is in fact a couple real differences between lead and steel. Lead still hailed as the best patterning material for a shot shell and steel has almost no give. Something very important to understand is that steel shot reacts differently in chokes making a making a modified chock behave like a full choke and in almost all cases a full choke not usable at all.
Small Upland Game
The two most popular shot sizes for small game are #8 shot and #7 1/2. many upland hunters could debate hours on the difference between these two shots but we are going to make things basic. #8 will spread quick and are very small pellets making small game like Woodcock a great selection for this shot size. Not to say this cannot be used on bigger quarry like Ruffed Grouse. Some hunters like to make the jump between #7 1/2 and #8 depending on the amount of foliage on trees. Opting for the heavier hitting #7 1/2 in that ticker cover.
It is important to remember variety is an option with double guns, pumps, and semi autos. Upland hunters will often start with a #8 and follow it up with a #7 1/2 for a longer range shot if necessary. We suggest that you experiment on what you like and in turn learn what works best for your purposes.
Bigger Game Birds
When it comes to bigger quarry like Pheasant we will need a heavy hitting pay load. For game birds of this size the two most popular shot sizes are #6 and #4. These shots have much larger pellets than there previously mentioned cartridges translating into deeper penetration and more knock down power.