Thanks for the reply Kato, I thought this might be the case although I had hoped that it wasn't.
At one time when I was originally searching for it, I was given to understand
The Armory was a cheaply produced supplement meant as practically a freebie for conventions and so on (anecdotal story and nothing I've seen in the last ten years has supported the claim). It was printed in 1983 by a publisher that no longer seems to be in operation and there is no ISBN from what I can find, all of which leant some initial credibility to the freebie claim.
With a little bit of checking on the net just now, there are copies for sale on Amazon, with an Amazon "ASIN" ID because there is no ISBN. A hell of a coincidence because there were none listed on Amazon, EBay etc. etc. for the last few years from what I recall.
Amazon ASIN: B0006EG1YY
USA
https://www.amazon.com/Armory-Vol-Gu.../dp/B0006EG1YY
UK
https://www.amazon.co.uk/d/cka/Armor...ent/B0006EG1YY
The Amazon page shows the later (I think third) print release with the colour cover, the copy I have appears to be the first printing with no proper cover.
There's a very small entry for the book on Wayne's Books, near the bottom of the page that shows the covers from what I think are the second and third printing.
http://www.waynesbooks.com/Weaponbooks.html#kd
If nothing else, at the very least, I might have made someone aware of this piece of early Kevin Dockery work. It was overshadowed by his much more comprehensive later book
Edge of the Sword Volume 1: Compendium of Modern Firearms.
The Armory is almost in the realms of "the forgotten" these days, such a rarity that it's practically a unicorn - often wished for, sometimes seen, but rarely possessed.