Swiss M 1963 Experimental US M16 bayonet / Dutch Stoner bayonet.(No ref.)

Dutch Stoner 63 A1 rifle or US M16 rifle. Serial number W  669280 on ricasso. Minty blackened double edge blade with serial number and Swiss maker's logo on ricasso. F W + in a circle (= Wenger in Bern). Excellent black ribbed circular grip with unusual US M 4 style press release and mortise slot in blackened pommel. Blackened crossguard with muzzle ring MRD 22 mm. 
Black plastic scabbard with green vinyl frog is marked Fasler 5034 Suit

Believed to be a prototype for the Dutch Stoner 63 A1 rifle and/or the US M16 rifle. 
Very rare prototype bayonet