This extremely hard to get stripped bolt was made by Fabrique Nationale D’Armes de Guerre, S.A. Herstal Belgium , commonly known as FN. From 1948 to 1952 FN made Mauser trainers in .22 cal for their own Army and Navy, also for the Belgian Congo (Force Publique) and for Israel. Rifles were identical to the 98K in every respect except for the rear sight, the bolt assy. and the barrel being a .22 cal.
Get them while they last and own a piece of history, or use your imagination and sleeve that worn out barrel and make a .22 cal trainer of your own…..