Shot
The gem of the shotgun, hence the name. This is where the great versatility comes in for shotgun shells—there are literally thousands of choices available and it’s important to have a general idea of what they are capable of.
The following table will help you understand the sizing of shot that classifies the most common shot sizes used:

Here are the best loads for your home defense shells:
• #1 buck shot—.30 caliber pellets ~11 pellets per shell
• #0 buck shot—.32 caliber pellets ~9 pellets per shell
• #00 buck shot—.33 caliber pellets ~8 pellets per shell
Noticing that the number of pellets decrease as the size of each shell increases, be sure to keep in mind that less pellets that are shot at a target, the less chance there is for contact. A 0 or 1 buck is a great combination of stopping power and spread considering that 9 .32 caliber balls fired at the same time is a good amount or lead and power.