I recently bought an old(?) shotgun from an Estate sale. It is a Winchester Model 12-12 GA Full. On the bottom, where you load the shells it has 301033 -TRAP- stamped into the steel. Directly above it the same 301033 is stamped into the barrel. It has nickelsteel stamped into the barrel before Winchester. The barrel is 18" long. The gentleman I bought it from said it was a Police issue weapon he called a "street sweeper". Said the barrel was cut down from the factory to fit in the "rack". The buttplate is a hard black plastic plate, the slide is engraved, but the stock is plain. Any help identifying this shotgun will make me a smarter man!