I was looking at the Lyman 5A post when I saw M. Petrov's post and my memory got jogged. 
In the late 80's while working for DoD I ran a Preaward Survey on the Neidner/Niedner Fire Hose Co. in far northern Me. 
They had bid on selling fire hose to the Govt., I was there to see if they had the ability to deliver.
I talked to the Niedner guys for several hours, nobody there had ever heard of A. O. or the guns or any of that. 
The Neidners and A.O. for a while were in the fire hose game.
In the end we found that the company and production was in Canada, and for good reason we had to turn the survey over to the Canadian office.
I meant to write this down and send it to Mike Petrov, who was deeply into Neidner-and was able to spell the name correctly-but just plain forgot until now.
These surveys were very interesting, I also did the survey on Saco Defense/SIG/Alusuisse when they and Beretta were the sole remaining contenders.
Hi Mike;
joe b.

Hi Guys. First off, Happy Turkey Day!
Would either of you know who I can contact about info on a Neidner barrel? Phone, email and post would be great if you happen to know, Thanks in advance. Jon