Berry's Manufacturing 414 - WSM Blue Ammo Box - WSM. s Ammo Boxes are made from high impact polypropylene for increased strength against cracking chipping warping expansion or contraction. Model #414 50 round boxes feature our easy-to-open lid. They are stackable they carry a lifetime warranty and they are made in specialized factories. Specifications for Berry's Manufacturing 414 - WSM Ammo Box: Manufacturer: Berry's Manufacturing Fabric/Material: Polypropylene Package Contents: Berry's Manufacturing 414 - WSM Ammo Box Berry's Manufacturing 43974: 414 - WSM Blue Ammo Box - WSM