When you don't know exactly what you need, I believe you can't go wrong with a Leupold VX3i 3.5-10x40. It's the standard for the upper end of the lower end.

Why would you want a 30mm tube on a hunting rifle? It adds weight, looks like crap on a nice classic rifle, and is completely unnecessary. You won't need to dope up a shot at 500 yards with a 243 in a hunting environment, and even if you wanted to, you can get that done with a 1" tube. 30mm tubes being the smallest tube size from Vortex rules them out IMO.

The Leupold is on sale right now for $349.99. That's a good scope in that price range.