<page_title> NATO EPVAT testing </page_title> <section_title> Proofing </section_title> <table> <cell> 5.56 mm (5.56×45mm NATO) <col_header> Calibre </col_header> </cell> <cell> Designed to chamber NATO ammunition <col_header> Specific Weapon Detail </col_header> </cell> </table>
The proof for ammunition of NATO calibre was 5.56 mm.