Can you buy a rifle barrel for a savage 220A?

Nope. Many top break RIFLES may have shotgun barrels, but the reverse is not true. The action of a shotgun is built for much lower pressures than a rifle produces.

Well, yes and no. The rifle version of the 220A was the 219, and barrels were made in .22 hornet, 25-20, 32-20,or 30-30. However, they have been out of production for some time, so they will be hard to find. The action is not designed for higher pressure cartridges such as .308, etc.