Re: Bullet Length List?
In place of real bullets to measure, I have used the advertising chart by the different manufacturers that show pictures of all the bullets they make or the pictures for the bullets in manuals. While the pictures are not necessarily to scale, you can determine the bullet length by scaling it based on the measurement on the picture of the diameter of the bullet. It is simply a ratio. This is accurate enough to do the Greenhill formula calculation. It is not sufficient to measure bullets of one weight and assume all bullets of that weight will be the same length. The ogive chosen by the manufacture, the shape of the bullet base, and the makeup of the bullet tip all influence the length. You need to measure (or do the scaling thing from pictures) to get an accurate length measurement for barrel twist calculations.
Be aware that while theoretically too fast of a twist for a particular bullet (over stabilization) is deemed OK, it is not necessarily so in reality. The spin RPM's are huge and if the bullet is not made to sustain that fast spinning, it will fly apart before reaching the target. This is not folklore as I have had it happen to me (223 caliber 55 grain run-of-the-mill hunting bullets in a 7.5 inch twist barrel). Only reducing the load level (bullet velocity) and picking a better bullet (varmint bullet) allows the gun to shoot 55 grainers but they do not shoot nearly as accurately as the correct longer bullets for the gun's twist.
Last edited by LDBennett; 08-27-2012 at 08:50 AM..