The clearest case of a flat base bullet out shooting a boat tail was a 300 Wby MkV which a family friend brought out to shoot on our range in 1965. I was pretty excited because I had not seen a Weatherby in action before. He fired a 3 shot group at 100 yds, using 180 Hornady bullets, and they formed a perfect triangle 1 inch wide. He then fired three of the same load but with 180 Sierras on top. This load produced a nice eight inch group. The long, oversized throat in the Weatherby just didn't like Sierra boat tails. Norma 180's, with a much shorter boat tail and a somewhat blunt nose, shot as well as the Hornady bullets; so did Speers.
I had the same experience when shooting .308 bullets in my 303 British. Any flat base bullet shot quite well but a Sierra boat tail would barely stay on the paper. GD
