For LONG RANGE HUNTING the right answer is always -first cold barrel shot -hits it's mark. That's what accuracy really is, and if group shooting at all, the spread should be taken to center of bull.
This is also from field rest and conditions only. No BR, no bench, no martini(shaken, not stirred). And finally, it includes shooting as a 'system' including strategy, ranging, stalking(with all equipment), condition measurement, calculations, corrections, timing, and the sense to know all is right before commiting(with your one shot) to hit your mark.
BR shooting is about PRECISION, CONSISTENCY, SPIRIT OF COMPETITION, and not at all about ACCURACY. In fact, most winning groups in BR are quite larger in MOA to their actual mark, and many BR guns would fair poorly in cold barrel accuracy. The equipment isn't designed for accuracy, the loads are not developed cold, and competitors rely on sighters instead of ballistics. The challenges are different.
I wouldn't rule out factory guns and factory ammo for accuracy potential based on poor grouping.
Forget grouping, it matters not.
Testing them in grouping is of no value as you are testing them -out of their element.. Far away from their design..
Instead, develop a cold barrel load, and shooting system, which you can rely on to hit nearest your mark. Do this with each gun in your safe and I bet you'll be surprised by the new order they fall into w/resp to accuracy.
There was a gunrag test that raised a stink a few years back. Several factory rifles and a BR gun built by Speedy. All shooting factory ammo. Speedys gun lost to the lineup, and of course this irritated many. Didn't surprise me at all.
I engage in a local accuracy contest each year(for the past 2). 1 shot at 200yds, 1"bull, off a feed sack full of dirt on a weathered(and warped) picnic table. You make it, you go to the back of the line. You miss, you're out. 1 winner takes all. It usually starts with ~35-45 shooters who prep for this way ahead of time but only one shoots at a time.
It went 9 rounds the year I won with a 26wssm custom. But last year I was whipped unmercifully(and so was everyone else) by a brand new Savage with Hornady 22-250 ammo. That surprised me, and another who had pre-demonstrated that he could cut a ragged hole all day with his LV6ppc. But it shouldn't have surprised us. We weren't hitting the center, the temps changed, the bag was packing, and timing between shots was ever changing(from hours to minutes). I'm sure it sounds easy, but nobody has won it twice in a row. And group shooting does not prepare you for this. It takes alot more work.