It is only surpassed in calibre by the British Mallet 's Mortar and the American Little David mortar ( both 36 inch ; 914 mm ) .
A few other huge guns were never fired in anger : the French Monster Mortar ( 36 French inches ; 975mm ) , the British Mallet 's Mortar ( 36 inch ; 914 mm ) and the American Little David mortar ( 36 inch ; 910 mm ) .