MotorcycleR&B

Have you thought of getting a hasp welded to an ammo box? Your local backstreet car repair shop should do it for it cheaply. Drilling in an ammo box would work if you do a few things to prevent rust and water ingress. 1) paint the holes after drilling to cover exposed metal. 2) use stainless bolts. 3) add silicone washers each side of the hole when you put the bolt in. Rubber washers would do but require maintenance, whereas silicone will last years.