A boat tail's primary advantage over flat base bullets doesn't show for some distance, and it all comes down to too many factors to give you a specific distance. The boat tail design helps the transition from supersonic into subsonic velocities, which depending on what you're shooting, may occur at 700 or so yards all the way out and beyond 1000 or more. 2-300 yards will not show you any advantage over a flat based bullet at all.
"Why is is called Common Sense when it seems so few actually possess it?"
Guns only have two enemies: Rust and Politicians.