Internal workings.
air, metal,
gunpowder and bullets
Adolf Hitler
Inside the barrel.
Inside Edition - 1988 Top Gun was released on: USA: 3 May 1989
Inside Edition - 1988 Gun School was released on: USA: 30 August 2013
inside a locked gun cabinet
The Winchester Rifle.
Best known was the STEN gun.
Grooves on inside of the barrel= a RIFLED firearm- the grooves are known as rifling. Grooves on the outside of the barrel= fluting, done to reduce weight
If it is inside and the BB doesn't leave the building. It is against the law to shoot your BB gun outdoors.
Grooves cut into the inside of a gun barrel for the purpose of spinning the bullet when fired.