Any questions yet?
Finally, we'll cover Shotgun Ammunition, also called shotgun shells. Shotgun bores and shells are measured in gauge, where the number refers to how many lead balls that diameter would be needed to make a pound. So a 12 ga. is larger than a 20 ga. since if you had a pile of 12 balls that weighed a pound and a pile of 20 balls that also weighed a pound the balls in the 12 ball pile would be larger than those in the 20 ball pile. Make sense yet? Smaller gauge number, larger diameter.
Shotgun shells are built similar to the handgun/rifle cartridges except for a few differences. They have a primer and case, but a shotgun case is plastic. The powder is the same, but the shotgun shell has a "wad"--another piece of plastic to separate the powder from the shot. The shot is a bunch of little balls usually of steel or lead and can be purchased in various sizes. Some shotgun shells are loaded with a bullet called a slug instead of shot. Then the plastic is folded over and sealed at the top to hold it all in.
Now here's your new assignment. Find out what ammuntion you have at your house. See what you can identify . . . :)