Where can you buy ammunition for a Winchester 10 gauge lever action shotgun?
Any sporting goods store should have at least a few boxes of 10 gauge shells, but probably not a large selection. You have a shotgun that is between 76 and 119 years old in 2006. Before you buy any ammunition, have the gun checked by a competent gunsmith and if he approves it he should also recommend the proper load. Even the oldest of these Winchesters should be OK with smokeless powder, but I doubt if any would stay together through a box of heavy magnum shells.