$100 - $200. Belgium produced many, many cheap shotguns in the late 1800s and early 1900s for export, and also some very fine guns. However the vast majority were what are referred to as hardware store guns, i.e. they were sold in hardware stores, general stores etc for a few dollars. Most of these are best used as wall hangers, just hang it over the fireplace and look at it.
There is a long list of shotguns that are marked Royal, but I cannot find the United Arms part of your marking in my lists. All that I do find are attributed to Anciens Etablissments Pieper in Leige, Belgium, so I would bet on that being the source of yours, too. Since this version of the company name was first used in 1905 and the export of civilian firearms from Belgium ended when the Germans invaded in 1914, that would make your gun right around 100 years old.
A rifle.
100 USD or so.
Knowing the gunmaker's name would help. If he's a nobody, it's a decoration worth a couple hundred bucks, but if he's somebody important and known for his craftsmanship, it could be thousands.
it would be stamped on the right side of the barrel.
Browning imported guns never did say "fabric en belgium". Those guns that were made by FN were all stamped "made in Belgium" on the barrels, for those guns that were made for Browning. There are Browning patent guns made by FN that were sold outside the US and not imported by Browning that may have said fabric, but not on a Browning Arms Co. gun. Browning stopped production on the A5 in 1976 when production began in Japan. Any gun no matter when it was made in Belgium would be stamped made in belgium. Different models were made at different times and production by FN varied as to when they ceased.
about $3500
Possibly a BAYER 12 Gauge side by side ? Mine has two hammers and triggers. The trademark of a knight on horseback is inscribed on both barrels, and also 'Anc.Etabl.Pieper Herstal Belgium' inscribed on the barrel rail. Have any older shotgun checked by a gunsmith before using, it may not be up to modern loads. I cant find any other markings except for Occidential stamped on the side and it has a police shield on the but of the handle
Made in 1929.
The barrel will be stamped "made in belgium" or "made in japan".
Made in Belgium.
It was made in 1964.