I'm not sure but it looks like a Model 1898 rifle built probably in 1901 that got beat up and damaged pretty bad. I suspect the muzzle was damaged and the rifle was cut back and someone cut a dovetail relief in the end of the rifle and tried to solder some kind of sight on but it didn't hold well. The stock was cut back and filled with a filler piece as discussed above.

I'd suspect the bore is not very good from the looks of the exterior of the rifle.

Even though, I'd have a new sight put on, clean it up well and have a gunsmith check the chamber and bolt and make sure it's strong enough for shooting. Then I'd get some ammo and blast away. Even if the bore looks crappy, it still is probably a great shooter!

Good luck. I'd like to hear more opinions.