helotaxi
05-22-2011, 11:00 PM
Bearing surface has nothing to do with stability either. Look at the two formulas for determining bullet stability, the Greenhill formula and the Miller index, and what variables go into those formulas. The only ones that are taken from the bullet itself are the diameter and the length. The ratio of length to caliber is the relationship that matters.
Bearing surface has an effect on the way that pressure builds in the chamber, more bearing surface means that more of the bullet is contacting the rifling and more friction from it moving down the bore. Examples of the irrelevance of bearing surface to stability are the Berger VLD bullets (very low bearing surface but very long, requiring a faster twist than similarly weighted bullets with a more conventional profile) and the Sierra .224 77gn MatchKing (relatively blunt ogive and a lot of shank and bearing surface but not requiring as fast a twist compared to even some lighter .224 bullets).
You just explained why bearing surface is important.
"Everything" is important. The question is "what is it important to?" If the "something" is bearing surface, the "what" is pressure. Exactly squat to do with stability. The discussion is about stability so bearing surface has no place in the discussion.
Bearing surface has an effect on the way that pressure builds in the chamber, more bearing surface means that more of the bullet is contacting the rifling and more friction from it moving down the bore. Examples of the irrelevance of bearing surface to stability are the Berger VLD bullets (very low bearing surface but very long, requiring a faster twist than similarly weighted bullets with a more conventional profile) and the Sierra .224 77gn MatchKing (relatively blunt ogive and a lot of shank and bearing surface but not requiring as fast a twist compared to even some lighter .224 bullets).
You just explained why bearing surface is important.
"Everything" is important. The question is "what is it important to?" If the "something" is bearing surface, the "what" is pressure. Exactly squat to do with stability. The discussion is about stability so bearing surface has no place in the discussion.