Magazine tube nut for attaching Nordic Components extensions. Manufactured from aluminum billet and anodized matte black.
Click this link to find the extension tube for your firearm: Extension Tube
Big Book Catalog, Issue:70, Page:199
Big Book Catalog, Issue:71, Page:205
Big Book Catalog, Issue:72, Page:204
Big Book Catalog, Issue:73, Page:206
Big Book Catalog, Issue:73, Page:225