45-70 Government cartridge - AVOID the two hotter loads. The only word of caution I leave you with is that there are THREE separate loadings for the. I found a very decent resource in John Wolf's booklet on the Trapdoor.

It is a good idea to do your homework on the rifle and the ammunition/sights. With the 'slow lock time' learning proper follow-through is essential when shooting these rifles. When these rifles left service, they were sold off very cheaply - and the civilian owners often neglected to properly clean and care for them. The interior of the barrel may need a good cleaning. Any abuse you may find will have been AFTER the rifle was declared surplus. These rifles didn't see a lot of abuse, and finding one in great condition isn't all that hard to do. The actual serial number is stamped on top of the tang just to the rear of the breech block.

I agree that the first 'serial number' with the P is likely a 'Rack Number' - meant to facilitate issuing the rifle to the right person. Nice rifle! Can't tell you much about it, except it is the 1884 version with the breech block style and the Buffington rear sight.

Springfield model 1873 serial numbers