Thread: Case neck sizing and effect on accuracy

For users of bushing dies, do you think that sizing just a small amount of the top of the neck can be used as a means reducing variation in the grip on the bullet brought about by the unavoidable spread in neck tension, and so have a beneficial effect on ES ?

Why would reducing the amount of neck holding the bullet have an adverse effect on concentricity, provided whatever sizing has been applied has been done so with minimal runout? Prior to ignition the unsized base of a fire-formed case neck is is snug fit with the chamber, the bullet shank is also sitting in the freebore - so there should be no difference in the way the bullet is presented to the leade prior to ignition. If reducing the length of neck holding the bullet does have an adverse effect on accuracy, it must be a dynamic thing, the effect being felt once the bullet is on the move. Perhaps having the neck sized for the entire length maintains the position of the base of the bullet for that little bit longer, or aids in a more even movement of the combustion gases around the base of the bullet at that critical moment, assisting the engraving in being marginally more symmetrical?