It's kind of hard to find such a scope in the six hundred range but not impossible. I would suggest Vortex Viper PST 1-4x24mm w/ TMCQ MOA PST-14ST-A, it is [a href="http://perfectriflescope.com/the-best-vortex-rifle-scopes-review"]one of the best Vortex scopes[/a], it is much cheaper than $600 at the moment (some $470 Amazon) and it has an adjustable zero stop.