I'm pretty damn happy with my Primary Arms HUD DMR ACSS scope on my 6.5 Grendel. I have no problem ringing steel at the Sacramento Valley gun range steel range which goes from 50 yards to 550 yards. Zero'd at a 100 yards and good through the whole range.
I recently stretched the legs on my PA 4-14x44 ACSS and I came back hating that reticle for LR work (went out to 1k). From the lack of a center crosshair to the BDC obscuring the mil dots to the lack of mil hashes for wind holds under 2 mils, it’s a one trick DMR pony (assuming the BDC works for you and your load). I regret not getting the cheaper mil dot version now. My copy also had over 5% tracking error at 10 mils and the 6 mil dials tripped me up for a while.
EDIT: I just reread the thread title and while the ACSS is fine inside of 500, I wouldn’t recommend paying the additional $50 for it.
A used Leupold Vari-X II or Vari-III 3-9x40 maybe.
Kind of interesting you don't feel you need a tack driver, but will be hitting a 4" wide target at 500 yards with a couple boxes of ammo for practice. Not saying you can't, just not easy. Would probly suggest starting on pictures of groundhogs at that distance before taking a shot at a living animal.