Out to 500-600 or so yards, a custom turret is not bad. Out past that, they are not that accurate unless you hunt at the same elevation/density altitude/temp. So if you change from a high country late summer pronghorn hunt to a late season desert mule deer hunt, your drops will be off.
6.5mm 140 Hyb @ 3035fps @ 600 yds, 800 yds & 1000yds:
7000' AMSL & 85*F: 53.4", 113.9", 202.9" drop
2000' AMSL & 35*F: 57.8", 125.8", 229.6" drop
Better to get a good ballistic app, or even a good programable rangefinder that will take all that into consideration.
I have a Labradar, you are more than welcome to come shoot with me anytime.