Some bullets, like the 168gn SMK .doesn't stablize 'til about 180yds,so it's hard to say. These new loong,high B.C. bullets may take more.
Glenn Newick,in his book The Ultimate in Rifle Accuracy,emphasized the importance of gettting the bullet stabilized as quickly as possible.
Flat based bullets are "supposed " to stabilize quicker than boattailed bullets. In the barrel,the bullet rotates around the center of mass...after it leaves the barrel,the bullet rotates around the center of gravity....HOPEFULLY they're the same,but not always so.. Thats the importance of being sure the bullet starts centered into the rifling.
Good luck and stay safe.
