Actually, the opposite is often true. Most benchrest shooters who shoot out to 200yds or so, regularely shoot flatbase bullets. Flatbase bullets are easier for the manufacturer to make consistent.
In factory chambers with looong freebores the flat base bullet may shoot better because you can seat the bullet out a bit farther and still m,aintain good neck tension. Obviously, the tails of boattail bullets provide zero neck tension and may limit the cartridge OAL.
The benefit to boattail bullets doesn't really begin until you are shoooting out past 400yds. For most hunting this isn't an issue. Lastly, boattail hunting bullets have a greater tendancy to suffer from jacket/core separation after impact. However, the newer bonded core bullets should eliminate this problem if you choose them.
[ 11-01-2004: Message edited by: Varmint Hunter ]