Weight doesn't necessarily correspond to length of the projectile. 62 grain ss109 (green tips) are longer than they would be if they were lead core FMJs because they steel is less dense than lead.
Remember weight isn't really what corresponds to the twist rate needed. What you are more interested in is overall projectile length. The longer the bullet the more twist needed. You'd find that lead free projectiles are way longer than their overall weight would suggest.
It just so happens that most bullet are lead core FMJ. So most people automatically assume that the lighter a bullet is the smaller it is.
Assumption is the mother of all ****ups.
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