Going from the stock it looks a bit like a Pfiel deluxe (if so, it'll be 105cm long)...but the breech block looks different...Mr Hiller's book (p188) has a bit of info on these...
Edit: Steve, do us a favour and measure the stock-end, for depth and width, please. I'll see if I've got a buttplate that'll fit...it saves Guy sending me a template