Lands and grooves.
Essentially the same
Inside the barrel.
You compare the rifling marks on the bullet to the rifling in the barrel. You can also compare the firing pin mark on the primer to the firing pin on the gun.
Type of rifling/twist.
Rifling will leave grooves--impression in a bullet. These grooves can indicate the manufacturer of the gun that fired that bullet, AND, if there is a suspected gun in particular, microscopic variations can be used to confirm or refute that gun's involvement to a high degree of certainty.
Grooves cut into the inside of a gun barrel for the purpose of spinning the bullet when fired.
shot gun and very early muskets
The twist on the inside of a gun-barrel is called rifling. I dont know the specific pitch of the rifling in this particular gun but thought you would like to know the proper terminology.
Rifling a gun barrel causes the bullet to spin when it comes out. This makes the bullet fly more straight and greatly improves accuracy. Much like a spinning football spirals.
Smooth bores are bores or barrels in guns that do not contain rifling. Rifling is made up of lands and grooves that cause the bullet to turn within the barrel of the gun. This turning gives the bullet and gun its accuracy. A smooth bore gun is much less accurate than a rifled bore gun.
broach is the tool to cut rifling.
because the rifling in the barrel makes it go straight.