March 8th, 2017, 02:05 PM
Join Date: Apr 2015
Location: North Carolina
Originally Posted by Puccini
It's not only the weight of the bullet that determines accuracy in any given twist. It's also the shape of the bullet.
The more metal that contacts the bore/twist the more accurate.
Thats why 6.5x55 bullets are generally more accurate. They have a long shape and more contact with the bore.
Well... yes and no.
It really has nothing to do with how much of the projectile touches the bore but where it touches the bore, the "wheelbase, so to speak.
If you look at the projectiles below, they really only contact the bore in two places, the rotating band just above the boat-tail and at the bourelette at the start of the ogive section. The portion of the body between these two areas is relieved so as not to touch the bore.
An extreme case:
The longer the distance between the two furthest bore contact rings are, the less likely the projectile will be cocked off-parallel to the bore centerline. Also, the smaller the magnitude of the maximum crookedness.
Last edited by lysander; March 8th, 2017 at 02:29 PM.