George Klingelhofer etc (attr.).
Maker possibly George Klingelhofer, Gustav Kochler or Gotleib Krug.
With thanks to Sean Campbell, imaging manager of the Buffalo Bill Centre of the West in Cody, Wyoming, for permission to post these pics of a gun held in the Cody Firearms Museum. The blurb accompanying this gun follows.
Accession Number: 1988.8.2441
Date : 1860-1880
Dimensions: L: 47 in, Barrel length: 24.5 in, H: 7 in
Credit Line: Gift of Olin Corporation, Winchester Arms Collection
Remarks: maker possibly George Klingelhofer, Gustav Kochler or Gotleib Krug (--Simeon Stoddard, 2/8/94)
Inscription: top of barrel, forwardof rear sight: G.K.
Synopsis: firearm- spring-piston- breech-loading- airgun- single shot- Unknown- wood- brass- steel- top of barrel, forward of rear sight: G.K.- .28- maker possibly George Klingelhofer, Gustav Kochler or Gotleib Krug (--Simeon Stoddard, 2/8/94)

