I recently published an article on flat-base versus boattails:
1) Boat-tailed bullets do tend to destabilize more when leaving the muzzle than flat-based bullets, due to more powder gas blowing by the angular base during muzzle exit. This is why short-range benchrest bullets are flat-based, or have very slight boattails.
2) But te reason higher-BC bullets tend to group better at longer ranges is not primarily because they take longer to "stabilize," but because they drift less in wind.
3) Most shooters (especially hunters) don't get this: Instead they assume groups are relatively larger at ranges beyond 100-200 yards because bullets are becoming "destabilized" as they slow down.
4) This is actually the opposite of what happens, because bullets in flight are affected by two different forces: air pressure on the front end, which tends to destabilize bullets, and gyroscopic stability from the rifling twist. Velocity slows much faster than bullet spin, so bullets fired from a sufficient rifling twist become MORE stable at longer ranges, due to lower pressure on the nose--at least until they drop to around the speed of sound, which doesn't happen with typical hunting bullets.
5) Wind-drift increases at about twice the rate of range: A bullet that drifts half an inch at 100 yards in a 3-mph wind will drift around 2 inches at 200 yards in the same wind--and 8 inches at 400 yards
So yes, boattails can be less accurate at shorter ranges, but become more accurate at longer ranges due to less wind-drift. And most hunters have no clue how much even a 3-mph breeze (often consider "calm air") can drift a bullet even at 100 yards. Since wind is rarely absolutely steady, groups "open" up at longer ranges, unless the shooter can compensate accurately.
Thanks for your reply MD.You have a way of explaining this that even a Luddite(me) understands.
