50 x Units (2500 Rounds). All Berry’s Ammo Boxes are made from high impact polypropylene for increased strength against cracking, chipping, warping, expansion, or contraction. Our Model #407 50 round boxes feature our new, stronger, flip-top design, allowing the securing of ammo storage with easy one-handed operation. Along with a translucent lid, they now come with a black base for increased strength and a clean look. #407 Ammo Box Cell Dimensions: 1.68 OAL x.