need help with 16 gauge

i would like to know what this gun is worth and any known proablems with it also can i take it to a smith and get it reamed to a 2 3/4 ?

it is a fabrique nationale d'armes de guerre herstal belgique

then under that it says brownings patent defose ... on the barrel it has acier specialthen has a lot of marks "some language"jap? it will shoot a 2 3/4 shell one time and will not eject it i think it is chambered for 2 9/16 am i right and can this be changed thanks