Correct firing pin protrusion is critical to the entire ignition
sequence. Elliptical face on the recording plunger allows accurate
measuring of both rimfire and centerfire pin protrusion to within
.0001". To Use: Unlock plunger, place gauge over protruding firing
pin, lock plunger, lift from bolt and mike overall length. Difference
between original length and miked overall length of body plus
plunger, is amount of pin protrusion.
SPECS: 1/2" (12.7mm) dia., .90" (23mm) lg. Hardened
plunger.
Catalog page 473