I have an unusual Mauser rifle. It is a carbine. It was made by FN in Belgium. No crest on receiver. 30 06 cal. All matching numbers. What is unusual about it is that the barrel is threaded at the muzzle probably for a muzzle brake of some kind. The front sight is set back a few inches from where the muzzle is threaded. It looks just like a Dutch police carbine except for the threaded muzzle. I have been looking everywhere for pictures of other guns like this but have not found any. Any ideas on this one? Thanks in advance.