Dustin's advice is very good. A lot (everything) depends upon what kind of gun you are talking about refinishing, and what condition it is in now.
When you say bead blasting, I immediately think of glass beads. There are several types of abrasive blasting that may result in a wide range of surface finish. Coarse garnet is much different (aggressive) than fine abrasive corn cob, crushed walnut shell, or soda (sodium bicarbonate) blasting. Even worn out glass beads will leave a much different surface texture than fresh new glass beads. Some of my co-workers who were too lazy to change it would let it get to the point where it became nearly as fine as talcum powder.
A silver finish on a gun is usually polished steel, or a case hardened surface that has lost its original colors. But it could indicate nickel plating. Bead blasting, even lightly, will result in a finish that is more matte in appearance, and polishing will be necessary to make it smooth and shiny again.
On a microscopic level, a smooth polished surface has much less surface area than any abrasive blasted finish. Any steel parts left in an abrasive blasted state will appear duller, and will be much more prone to oxidation (rusting) than a smooth polished surface. So some clear lacquer coating, or maybe a Cerrakote or Camo paint job may be used to protect an old barn or duck boat gun.
Few knowledgable people care for any good quality old gun to have that sort of finish. But if the gun is already in poor condition, and rusted/pitted beyond normal restoration, abrasive blasting is a quick. cheap, and easy way to clean it up. I wouldn't advise doing anything without knowing what make/model of gun it is, and the present condition. Too many nice old guns have their value ruined by good intentions.
