For me, beyond 450 is where .223 starts getting hard to hit smaller (say 2-4 moa) targets with, unless I'm very well supported and have all day. Past 600 is a real challenge. Just stepping up to 6.5 Grendel moves the "hard" range out to past 800.
Give me a 10 moa target, enough support, and enough time, and I'll hit it at 1,000 with .223. Ask me to hit a 4 moa target at 700 quickly and with less than perfect support, and there will be a lot of misses. The difficulty of all shooting is relative to target size, contrast, support, and time to shoot, but .223 practical effective range is 400ish yards.
Putting 10 or 20 moa bases on 1-6x scopes for .223 rifles just doesn't make much sense for the optic or the round. It's a mid range optic for a mid range round. My 16" AR shooting 77 grain TMKs at 2,428 fps requires 19.9 moa upward adjustment for 600 yards from a 100 yard zero. Your scope has 20 moa of adjustment per revolution.