It would depend upon a few variables you omitted, such as both mechanical and cosmetic conditions, and grips/accessories.
Let's assume it's Excellent with original grips, and you could say a fair range would run from $425 to $500 right now I would say. The market has softened considerably the last year. I have seen many priced higher, but not actually sell.
You can also go to GunBroker, search "closed" auctions, and look for those with a 2.5" bbl and actually sold, not just closed w/o bids.