That depends on the size of the shot in the 3 inch shotgun shell,and the weight of the shot.
The number of pellets contained in the shell will depend on the size of the shot.
pellets, powder
A 12-gauge shotgun shell typically contains multiple pellets, which are small, round projectiles inside the shell. The number of pellets in a 12-gauge 3" shell can vary depending on the specific type of shot being used, such as birdshot or buckshot. As a general guideline, a standard 12-gauge 3" shell with birdshot may contain around 1-1/8 to 1-1/4 ounces of shot, which can translate to roughly 200 to 300 pellets. For buckshot, there are typically fewer but larger pellets, with a 12-gauge 3" shell commonly holding around 8 to 15 pellets.
.410 shotgun shell either 3inch or 2 and one half inch
an egg
No, not advisable.
Steel or lead pellets... you know, the stuff they already come loaded with.
Remove the lead pellets from a shotgun shell. Reload it with rice and then shoot the little beast.
8 hours
Depends on the guage and length of the shell, and the size of shot used. It may be as few as 3, (.410 Buckshot) or as many as several hundred (10 g birdshot).
Depends entirely on the gauge and size of shell. Can vary from 9-30
OO Buck contains nine .32 sized lead balls.