What exactly is the breach?

[Booda Sack]

What exactly is the breach on a gun?
Or are they only on shotguns.
Kind of an odd question but I have my reasons.
Probably a stupid question aswell for people who know about this stuff.

 

[Rocket Executive]

The breach is the space between the bolt and the firing pin, right under the magazine on a non-shot gun.When the trigger is pulled, sear disengages from the breach block and the return spring drives the firing pin against a round in the chamber. Gas pressure from the firing of the round forces the breach block to the rear, compressing the return spring. The extractor, already engaged into the groove at the base of the cartridge case, extracts the case as the breach block begins its travel to the rear. The round is ejected out the right side of the gun. The breach block bent forces the sear down, holding the breach block to the rear and readying the gun to fire again. On a shot gun, there is no magazine and the shells are loaded directly into the breach when you cock the shotgun. I hope this answers your question, and any others you have you can post them on my Service Station thread, lol.

On the pic below, the letter C represents the breach. The H is the breach block.

Just don't hurt yourself or anyone else if you're planning to do some maintainance on your firearm. Never handle a gun if you don't know what you're doing.