That is a 1917 Enfield. They are a WW 1 era military action that was built by Winchester, Remington and Eddystone. The Remington actions are the most desirable then Winchester. The Eddystone's are prone to be brittle and shouldn't be used for a custom rifle. That one looks to be in really rough shape and appears to be missing lots of parts including the safety, bolt stop, ejector, trigger, magazine box and bottom metal. I have built a couple of rifles out of Enfield actions. They are a big heavy action and is best suited for large magnum calibers like a 375 H & H or 416 Remington.
