Boattail bullets are not necessarily more accurate. They're a bit more aerodynamic than a flat based bullet and will drop less. The difference only becomes significant at extended ranges.
Every rifle is a soul unto itself and will tell you what it likes to shoot best. Mid range bullet weights for caliber are usually what a rifle will like. Velocity is another critter altogether. Some like max loads others something less.
If you get into reloading, you'll learn that the distance the bullets bearing surface is from the start of rifling makes a difference in accuracy too.
The only way to learn the combination for your rifle is to shoot it a lot with different combinations.
One factory .30-06 round I've had good luck with is Winchester gray box 165 grain. You just never know until you try them for yourself. Premium might be the deal and it might not. Shoot and learn.