Colt Firearms Brass Bore Gauge Keychain

PISTOLS & REVOLVERS KEYCHAIN , a Colt Firearms bore gauge. Solid brass and measures 3 1/2 inches long. I understand these were salesman samples to give out to customers at gun shows and to dealers. The end of the gauge has a hole to add it to a key chain. The gauge has M.M. Scale to measure with. Sam Colt's success story began with the issuance of a U.S. patent in 1836 for the Colt firearm equipped with a revolving cylinder containing five or six bullets. Colt's revolver provided its user with greatly increased firepower.  "Abe Lincoln may have freed all men, but Sam Colt made them equal." This post-Civil War slogan would have been music to Sam Colt's ears had he lived long enough to hear it.