Dave, I realize that Ansley Fox got his own patents to build his Fox gun (and I am specifically referring to the AH Fox Gun, the other models are primarily known only to the most advanced collectors such as yourself); but, in my humble opinion, the patents he received for his lock mechanism was a modification of Hollenbeck's original idea, just as the sliding cocking plate on the barrel lug was a modification of Horne's patent. Please note that I did acknowledge Fox's modifications were ingenious; and that the finished result created an excellent gun (I also noted Horne's ejector patent was used only on the earliest Fox ejector guns). However, if my theory/s is incorrect, I bow to your superior knowledge.
