I live in England and collect cartridges. I have a box similar to what you describe but Remington Express 1 1/8th. ounce 2 3/4" cartridges. If it says 3" magnum it will be scarce. 3" chambered 16 bores were made but not many. I have some original Eley 16 bore 3" rounds but am yet to find a magnum chambered 16 bore gun. Just looking and I have two different sorts in different green and yellow boxes. I'm sure some Remington collector will come in on this. Lagopus.....