Hornady - Steel Dial Caliper No. 1 May also be used with

May also be used with sizing dies that use ¼”-28 or 10-32 thread spindles

Available in LH and RH

And the commercial die manufacturers have no set standards for the Expander button in their dies

and body to allow cases to fit in SAAMI minimum rifle chamber

Another method is to measure the neck thickness with a ball micrometer or Redding’s Case Neck Gauge

Hornady - Steel Dial Caliper No. 1 May also be used withStainless steel construction with shock resistant dial is accurate to + 0. 001". Four way measurement capability: inside, outside, depth and step. Slide may be locked in any position for precise measurements. Thumb wheel aids in easy opening and closing. Includes plastic storage case. (inches)