Try the Clearidge Ultra RM 3-9x32 AO. I have one on a CZ 452. It's about the same size as the Leupold, has very good glass, nice resettable turrets, and comes in different finishes and reticle choices (mine's a gloss w/ duplex dot.) It's price is pretty good, too (<$250.) And it has a lifetime, transferrable warranty.
The 504 is a pretty nice rifle and deserves a scope that matches it in scale and quality.
