Had a good search and this seems to be a consensus,
Flat-base bullets are inherently more accurate than boat tail bullets because it is almost impossible to form boat tails perfectly. Even so, over long range, a boat tailís ballistic benefits out weigh any manufacturing flaws.
There are a couple of drawback to flat-based bullets ballistic efficiency the first is that their center of gravity is more toward their rear, which doesnít help stability the second is that as flat-based bullets pass through the air, the air flowing over the bulletís surface wants to slam back together at the base which creates quite a bit of turbulence resulting in increased drag, both the problems are reported to be worse after about 350 yds as the bullet slows.
Boat tails increase the ballistic coefficient of bullets, which helps them overcome air resistance, turbulence and wind deflection. The shape also helps the air flow transition over the heel of the bullet and reduces the base diameter resulting in less base drag which helps over longer distances.
I have always used Nosler ballistic tips with boat tails for stalking with my 25-05 as I may need to take shots over normal shooting ranges due to the land I shoot over. If I know I'm sitting in a box I use a 303 with flat based sierra pro hunters, I recently found some of these for £11.40 a box of 100 in 25 cal so picked up 300 to try in the 25-06
22lr Anschutz XIV Carbine, 222 Tikka M55,
223 SGC AR15, Sig arms 25-06 SHR970 Deluxe, 12b Beretta 682 Gold E, 12b Fletcher English BLE, 303 RE P14 (Remington made)