I'm not sure where you hunt elk, but no way I'd want an 8x or 10x as my lowest mag available. I hunt dark thick timber part of the time where 3x is the most I'd want.
If I were you, I'd shoot that rig as is, you might like that scope and you won't have to buy a rangefinder. You can always sell it later.
Otherwise, if you really think 500yds will be your max, any 3-9 with a ballistic reticle would work. If you can find the old 1" Vortex Razor 3-15 you might be able to get one for $500, great scopes. But even the $99 Burris FFII would work. I'm not a fan of FFP on hunting rifles, but many are.
