Rabbitears, I find what you said to be most interesting. I pride myself on my knowledge of US Marshal arms. I've always been of the thougt that the Springfield Trapdoor was of the 1873 designation. I had one that was made in 1875 but it was still an 1873.
From the single shot Trapdoor we went to Krag Jorgensen, and from there to the 03 Springfield and yes we used the British Enfield. According to Alvin York, the 03 Springfield was a better rifle. He liked the sights much better.
But back to the Springfield Trapdoor, I was unaware that there was ever another designation than model 1873. Thanks for the info!