Straight up 284 in a long action is also a damn fine round if throated to take full advantage of the long action. When done so you can run the 168 - 180 gr class bullets seated so the case capacity is maximized (boat tail starts at the bottom of the neck) it's a winner for sure.

Only issue is getting brass, which if you take 6.5-284 and just neck it up works pretty well (Lapua makes it and it's not hard to find), just keep an eye on it for donuts. Getting your hands on Winchester 284 win brass is nearly impossible if you don't happen to know someone who's shot 284 for a long time and has some old Win brass they've saved.