You might get so many opinions that you head will spin.
Man size targets at 500 yards you can do with a huge variety of glass with little magnification w/o sacrificing field of view.
Assuming you are using std. military ball if you zero at 300 yards you have a range of 12" on plate out to 400 yards. (within kill zone)
At 100 and 200 is 4 and 5 inches. Out to 500 yards you hold a tad less x3 that (31" or a tad below 3ft)
With 10mph full value wind at 9 or 3pm then you will have to hold 1.5ft at 400 yds and a tad below 3ft at 500.
For a 5mph wind just half that. You can do this with a number of 1st or 2nd focal plane optics.
Among others I use a little burris timberline 2-7 in some piston carbines because it is small foot print and only 12oz.
This is good to 800 yards with 75gr TAP. But any of the above will work too.
For a light carbine for me having the variable magnification on a super light glass is something I like.
Now if you are going to be alternating targets at unknown distances or do ranging I suggest a 1st focal
and spend a bit more in something with consistent units of measure between stadia and adjustment
but it is not really necessary unless you want to be more accurate at longer distances and provide accurate ranging.
Also keep in mind ACOG provide amazing field of view that is something very desirable too.
It makes things a lot easier but in reality you could map your stadia in any scope to your loads and then work it out.
The key thing is to know what your loads are doing and what to expect at those distances and see what method
of correction seems more acceptable for you.
If you do not have ballistic software go to this from winchester and see if you can simulate your load and then
try to see how that would work with the stadia and formula you like.
Winchester Ammunition ? Ballistics Calculator
Pride and Fowler (rapid reticle) also have some good ones maped to std. service loads but anyone will work given that you understand
the correction on that given design. I would keep it simple and not too busy. Horus are nice but seem a bit cluttered
for the given purpose plus when mapped in the field they are not 100% accurate but they are pretty close though.
I prefer mil-mil or moa-moa because then I can do precise adjustment faster in consistent units should that be needed.
BDCs like ballistics turrets do not really work because if you move to a higher or lower altitude you need to convert the designated
drop in the comp to a meaningful correction.
But again for a man sized steel target at 500 yards even a BDC comp with some knowledge of how to map the stadia to std
units you could adjust. Slower in some cases but in most average ranges will be as rapid as the most sofisticated scopes.
Decent eye relieve and fast adquisition is something I look for when working at the lowest magnifications and close ranges.