It's possible to shoot 1000 yards with a .223. Just don't expect it to hit with more force than a spitball
A 75-90 grain Long Range .223 spitball arrives at 1000 yards with 300+ ft lbs of energy, about like a common pistol, .38-9mm. Not much in rifle terms but still a mankiller.
I HAVE shot .223 at 1000 yards. The tables say it ought to shoot right in there with a .308, but I don't think it will, quite. It will do very well at 600, though, granted those high BC bullets and top loads.
IF the 6.5-06 or 280 had been first on the scene, it is doubtful the 25-06 and 270 would even exist at the level of popularity they currently have.
Well, they WERE, kind'a sort'a.
The .256 Newton was very much a 6.5-06 except that for some reason Mr Newton felt compelled to cut off .050" of case neck and tinker with the shoulder angle. Available as rebarreled Springfields because WW I interfered with importation of Mauser actions, later in Newton rifles. The main limitation was 1913 powders. With IMRs it will push the .270 prettty hard. But nobody in the Big Companies paid much attention to Mr Newton except Savage and they did not have a long action to put it in. Hence the .250-3000 instead.
Some sources consider the .270 to be an Americanization of the 7x64 Brenneke. But we don't want no stinkin millimeters on our gun barrels. Why they picked the caliber of the obscure 6.8 Chinese Mauser instead of just calling it the .280 WCF is a mystery to me.