Beginning neck tension when beginning a new load

[Boomer79]

After measuring the outside Neck diameter with a bullet seated and it measures .338 from a .308 caliber should I start the neck sizing bushing at .335 as an initial size determination and then develop for the most accurate amount of powder and then adjust the neck sizing die plus or -.001?

 

[halfmoanut]

It will vary as you change bullets(&different lots) of the same bullet. The pressure ring on bullets vary. So that being said it doesn't hurt to have some variations smaller & larger. Another thing that will vary is neck thickness of brass, unless you turn each piece to the same wall thickness. .003 is a good starting point, however accuracy will dictate what is the best.