Shotgun barrel

[The Deer Hunter]

For a while I have wondered about the barrels of shotguns. Looking at the outside of the barrel you can see that they go from very thing near the breech to skinny in the middle and then wider again at the muzzle.

So the question I have is are the bores of the shotguns tapered like the outsides of the barrels? Or are they just straight?

 

[Dave McCracken]

The bore is a cylinder with a funnel at the back end we call the forcing cone and one at the muzzle we call the choke.

Barrels are thicker at the breech to contain the high pressures at ignition.

 

[The Deer Hunter]

Ok, that makes sense.

But then how do 12GA cleaning jags work?

 

[Dave McCracken]

They compress a bit.