I've sighted in two Savage rifles lately. One was a 22-250 and the other a .223.
The 22-250 shot five shots in less than .4" with factory loads. The .223 was just a tad larger but less than 1/2". Both had cheap 6-18x scopes. I doubt either guy had $800 in either rifle and ammo.
From shooting a lot of prairie dogs, in my opinion 400 yards is a stretch for a .223. Still The Varmint Hunter record for a .223 is 1023 yards. Special built rifle and scope.