When Dr. Gaddy passed away, I assumed that I would not get to see this display. I've seen it mentioned on-line elsewhere, but could never open the photography.
Do you know if he ever published anything else on the subject? All that I've ever been able to find was W. W. Greener's "The Gun, and its Development" and Walsh's(aka Stonehenge) "Modern Sportman's Gun & Rifle, Vol.1"