I am assuming that by "bench gun", you mean a benchrest gun? If you mean a benchrest gun, get ready to kiss about $4K+ good-bye. I would recommendeither 22 PPC, 6mm PPC, 22 BR, or 6mm BR. I would go with either a Stolle (Grizzly) or Nesika Bay (Classic R) action, either a Hart or Lilja barrel, and McMillan Light/Heavy or Edge stock. Of course these components will have to be expertly assembled by a gunsmith who is knowledgeable about building benchrest rifles.

Ifthat is not what you are lookiing for, then I would recommend the Savage Model 12 Long Range Precision varminter in .223 Remington.
http://www.savagearms.com/12PrecVarm.htm