Guns are another point of debate among trap shooters. If they are not trying to decide which is the best shell to use, then they are trying to find out which gun is best for them. The most important idea to remember when picking out a gun, is that as long the gun fits you correctly and you feel comfortable with it, then you will do well. Buying a $10,000 gun will not help with a shooter's score if it fits him poorly. Some of the top shooters shoot automatics that come right of the wall of a local gun club. If the gun fits them, then that is all it takes!
Guns are broken down into three main categories:

Automatic
With an automatic shotgun, a shell is loaded in the side of the gun, and the chamber is closed usually by pushing a button on the side of the gun or under the gun. When the shooter pulls the trigger, the empty shell (called a "hull") is thrown "automatically" out the side of the gun where the shell was loaded.

Pump action

A pump action shotgun is like an automatic, except to close the chamber requires the movement of the forearm forward on the gun. To expel the hull, the forearm must be pulled back. The forearm of the gun is the piece of wood that is attached to the underside of the barrel.

Break action

Here the gun literally breaks open to allow the removal of the hull and to place a new shell in the chamber. This is by far the most popular type of gun with competition shotgun shooters because break action guns usually have less mechanical breakdowns than pump action or automatic guns.