AAC and McClean 37mm cannon

I’ve just been doing some research into the 37mm cannon and ammunition offered by the American Armaments Corporation from 1934-194? Looking through their catalogue, I noticed an Automatic Naval Gun which looked kind of familiar… a check on my photo files showed that this looks like an exact copy of the pre-WW1 McClean cannon in 37 x 136R “Heavy One Pounder” calibre (no surprise, their small 37mm aircraft gun was a knock-off of a Puteaux design). AAC of course liked offering their guns with their own unique calibres, just to make sure that users of their guns would buy their ammo, so I suspect that their version of the McClean was offered in AAC’s 37 x 142R, which was just a slightly lengthened version of the 37 x 136R.

Any observations on this?

Also, is there any information, anywhere, on how many of which guns AAC sold to which countries? I know that several countries are supposed to have been its customers (most of South America, Dutch East Indies) but more detail would be welcome.

Thanks for any help.

I attach a photo of the McClean which I took about ten years ago in the Heugh Battery Museum in NE England. Those things crop up all over the place…


Have you seen the IAA Journal article American Armament Corporation 37mm Cannon Ammunition by Fred Butt, IAA Journal Issue 442, Mar/Apr 2005 pp 36-39?

Fred indicates that most of the AAC sales were to South American countries and the Dutch East Indies. Fred has/had access to an AAC catalog which may be a source for information you seek.


Thanks Brian,

Yes, I have a copy of Fred’s article (very informative) and also the AAC catalogue (I only know of one edition, but does anyone know more?) Neither of them answers all of my questions, however!