New member here

So, new member, and not really a gun person. However, I found an old FN rifle in the attic a couple years ago, and I'm hoping someone here can enlighten me with any info.
A friend has the rifle right now doing some research and seems to think it's a 9mm shotgun. Never heard of that.
This link is about all I was able to come up with a couple years ago......Nouvelle page 0
My "find" is the one at the bottom of the page.
I found this site this morning and since it's all about FN guns, it would be a good place for info.
Thanks to anyone who can help.