GO/NO GO Headspace Gauges For Many Popular Revolvers
Easy-to-use, double-ended gauge quickly, accurately checks headspace on any .38/.357 revolver whose cylinder chambers are NOT recessed for the case rim. Works on Ruger S.A. and D.A. (60-66), S&W's (60-68) and others with same GO and NO GO specs. Too much headspace can cause misfires and/or ruptured cases; too little causes jamming.
Big Book Catalog, Issue:68, Page:519
Big Book Catalog, Issue:68, Page:522
SPECS: 3" (7.6cm) x 7/16" (11.1mm). Hardened, ground tool