My guess would be a No. 4 Lee Enfield that has been sporterized to some degree - your pictures show that the ejector screw appears to be missing on the left side? Ought to be maker stampings, etc. on left side of receiver, also possibly serial number on receiver or on the wrist? Is difficult to tell from your pictures, but appears like the small pin is also missing from left end of the rear sight axle? To me that stock looks way too shiny/glossy to have been military issued like that - as if perhaps it was varnished by someone?