If you sight in the .270 about 2.5 inches high @ 100Yards you can shoot out to 300 yards with no adjustment just put the scope on the deer and pull the trigger. That's called sighting in for the maximum point blank range.
Similarly a 7mm-08 with a 140 grain sighted in 2.5 inches high @ 100Yards has a maximum point blank range of about 285 yards.
If you didn't know what you were doing and decided to shoot a Super Duper Magic Bullet that was lightweight and "faster" in the 7mm-08 say a 120 grain. Then the maximum point blank range would also be about 285 yards. That's where most people get lost they believe if they shoot a lighter weight bullet they can shoot further or something is happening that isn't.
Both excellent choices for whitetail deer, but there are a lot of misconceptions regarding ballistics and how to setup your rifle.
