Quote Originally Posted by ccdjg View Post
Well, Hawley's patent is dated 1869, Haviland & Gunn's first patent appeared in 1871, and Hawley's Kalamazoo was already being sold in 1870 in .22 calibre, so I think we can safely say that Hawley pre-empted H & G in introducing the .22 calibre onto the airgun scene. However, we still can't say yet if there were .22 calibre rimfires around before Hawley, which might have inspired him to adopt this calibre for his air pistol. We need someone with very early (pre-1870) firearm catalogues to do some research.

Although there are a lot of pre-1870 airguns known, these are in all sorts of weird calibres, usually very large. I have never come across mention of .22 calibre in any of these.
I think we are so near to an answer - that it is probably worth putting it as a separate question to others in this section. So if no one minds, I'm going to stop following this thread and pose this as a new thread as follows:

Is Hawleys's Kalamazoo the FIRST example of a .22 airgun?