Hello, I am new to this site and I'm happy to be here. I recently acquired a rifle that I need help identifying. I was told that this particular rifle would have been used by a Union soldier on horseback. Can someone offer some assistance in identifying exactly what I've purchased? Specifically, what year it was made? How made it? And any other anecdotical information. I've attached some pictures. What is not pictured is the folding rear site. Thank you in advance and I'm looking forward to the responses.