so that looks similar to the farco cc28 gauge shotgun, 51 caliber smooth bore I had years ago..it was bulk filled CO2 and it shot reloadable brass tube shells.. I also would run 454 lead balls in a sabot.. mine was chrome or nickel..it was made in the Philippines and I bought it from Air Rifle Specialist in Elmira New York.. ARS was the Logo for the company.. great old guy ran it, I'm sure he's long gone by now..
some time earlier this year there was a picture of one here on the forum, someone had just got a used one..
so the company Farco made them and as I understand they were labeled Farco for USA and if sold in the Philippines they would have labeled Parco.. a friend of mine brought back a Parco 22 foot pump survival rifle.. you would stand on the bale and hold it by the stock to pump it up.. around 100 pumps to full and then 20 shots before it needs pumping again..
Mark