Headspace gauge

Apparatus for measuring the headspace of a cartridge case using a caliper having a fixed blade and a movable blade, said case having a case head, a body, a neck, a tapered shoulder connecting said body to said neck, and a datum reference circle on said shoulder, the longitudinal distance between said case head and said datum reference circle being the aforesaid headspace, said apparatus comprising:

• a) a body member having a longitudinally extending bore with a preselected diameter and means for attaching said body member to one of the blades of a caliper so that the longitudinal axis of said bore is aligned with an axis connecting both of said blades;
• b) a bushing having a longitudinally extending bore therethrough of a preselected diameter less than said preselected diameter of said body member, said bushing further having at one end thereof an annular extension coaxial with said bore of said bushing and having an outer diameter preselected to closely fit within said bore of said body member;
• c) and means for fixing said bushing to said body member when said annular extension is positioned within said bore of said body member, said apparatus being further characterized by said preselected diameter of said bore of said bushing having a diameter equal to or substantially similar to the datum reference circle of a casing of a cartridge, the headspace of which is to be measured,
• whereby a cartridge case may be measured for headspace by (i) positioning the neck of the case into the bore opening at the end of said bushing, (ii) abutting the case head of the case against the other of the blades of the caliper, (iii) adjusting said blades of the caliper so that the end of said bushing is abutted against said shoulder of said case, and (iv) reading out from said caliper the headspace dimension measured thereby.