My dad loads all his own rounds for his Ruger 6.5 Creedmoor and has been getting them dialed in at 500 yds. His spreadsheet and data are pretty extensive for all the varying loads and projectiles. It is a serious endeavor to get the rounds matched to the rifle but once it is dialed in they can be nice and consistent.
He also has a Thompson Contender with a crazy barrel on it. 30-06 necked down to 7mm and he had to make his own brass for it. He has about 200 that are all indexed for the barrel and have a very precise load. One hell of a hand gun to fire and insanely accurate to well past 500yds, even for a 30+ year old gun.