Originally Posted by FutureMarine9
my shooting instructor told me that sub sonic ammo is more accurate...weather there's any truth to that i don't know but it's just a suggestion
Your instructor is correct.
This has to do with the transition from supersonic to subsonic. While the projectile is supersonic, it is in front of the sound/pressure wave. When it makes the transition, the sound wave catches up to it and whacks the bullet in the butt. This disturbs the stability of the projectile.
This is most noticeable when shooting light projectiles over a distance--and is a primary reason why high-power shooters favor the heavier projectiles that will hold their velocity for longer distances.
However, at bullseye pistol distances--25 and 50 yards--high velocity ammunition will not go subsonic. There is, though, the matter of recoil and recovery.
Finally, the .22 bullet can only be pushed so fast before leading will occur.