Flat Base vs Boat Tail bullets.
Flat Base - are more accurate when supersonic.
Boat Tail - are more accurate and efficient subsonic.
The Supersonic pressure wave negates any drag effect from the tail of a standard bullet. Boat tails are generally used to aid in production bullet seating.
What affects accuracy is how the bullet leaves the muzzle, and how the gasses (muzzle blast) affect it.
When a Flat Base bullet leaves the muzzle, it leaves immediately and cleanly. Gasses are directed out from the flat base perpendicular and away.
With a Boat Tail, the tail is still in the bore when the gasses are unsealed. The barrel is also vibrating, so the bore/bullet gap is also variable. These variable gasses are directed parallel, and then deflected off the tapered tail, imparting uneven perpendicular forces on the tail of the bullet while the tail is still in the bore, and as it exits.
Not an inherently good condition for precision.
When the bullets go transonic, the boat tail becomes much more efficient.
VLD bullet design may have improved supersonic ballistic coefficients, but they have not resolved the issue of bullet egress.
Red.
