I have a recent interest in older firearms and now have on loan from someone a trapdoor rifle that I plan to shoot. I want to make sure of what I have, but there is no "make" anywhere that I can find. The few other trapdoors that I have seen all say "US Springfield" on the side plate - this one only says "1884" (plus the picture of the eagle). The top is marked "Model 1873 US". I have attached pictures of these two markings. It does not appear that "US Springfield" has been worn off. Is this a Springfield (I can't find any mention of other Model 1873 trapdoor rifles - and this looks in other respects just like the other Springfields that I have seen)? Any comments on these markings?