Re: What is your comfort zone on taking game?
Talking deer; I seldom get a visibility beyond 200yd in brush, and try to minimize that with my 94AE 44mag. I doubt I'd be confident beyond 100yd, I use a dot scope.
For the open ground, I use a .30-'06 with 150gr Core-Lokt Express and a 2.5-10x42 MilDot, will take a quick offhand shot out to 200-250yd, and go maybe another 100-150yd if I can set up the shot with ample time to estimate drops.
For varmints, I use a .260 with 120gr Nosler Ballistic Tips and a 6-24x42 MilDot. 400yd with confidence; so far, successful at about 500 max. with a 'Whew factor'. The 95 V-Max vaporizes chucks and shoots flatter'n hell out to 500.
I like a flat shooting rifle, and project work with the .280 and 120, 140, and 150gr Nosler Ballistic Tips is telling me I'm on the right track. On paper, the 150 will do 1Kyd supersonic, shoot flatter, and arrive with more energy than the .30-'06. Hornady 139gr SST Superformance is simply awesomely accurate, and might reach 1Kyd supersonic, might not; but either way it's well worth paying $2 a shot for it. If I can do 1Kyd with a 140 out of a .260, I'm not gonna worry too hard about a 280 doing it with a 139.