Henderson & Sturm
Device for measuring dimensions to calculate the head space for guns
 An apparatus for measuring the distance between an outwardly extending planar surface on a head space gauge and a planar surface surrounding the head space gauge on the barrel of a gun. This distance is used to calculate the head space of a gun. A housing is provided for abutment with the planar surface on the barrel and has an opening for receiving a sleeve of a dial indicator. A set screw arrangement is provided for securely holding the sleeve of the dial indicator in a desired relationship for the measurement process. 
G
G01B
inventional
James R.
Anderson