In a rifled barrel, a series of lands and grooves impart spin to a projectile traveling through it.
In a smoothbore, there is no rifling, and the bore is simply round, though in the case of a shotgun subtle differences in diameter affect the way shot travels through the bore. Most rifles and handguns have rifled bores, and most shotguns have smooth bores. There are, of course, exceptions to this rule.


