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by Andrew Noakes, 18th May 2016

How to

Andrew Noakes shows how army surplus ammo boxes can be adapted to provide strong, secure, easily removable storage.

Military surplus ammunition containers are strong, waterproof and can be easily adapted to provide heavy-duty secure storage in your Land Rover at very low cost. They’re available in many different sizes and shapes, and they can keep tools, spares and recovery gear safe from prying eyes. We’ve picked a middle-sized box which fits neatly on top of the wheel boxes in a Defender load bed. We’ve modified the lid to give a convenient hinged opening that can be secured with a padlock, and it’s all been done without compromising the weather sealing of the box. What more could you want? Our ammo box is mounted to the Defender’s load bed so that it’s difficult for an opportunist thief to steal, but easy to dismount when we need to. And when it’s removed, it leaves an unobstructed load area with no protruding brackets getting in the way of any payload.


Ammo boxes come in a wide range of sizes, from tins used for small-calibre bullets to huge chests that are designed for transporting grenades and rockets. There are other similar military-type containers designed for delicate electrical equipment or medical supplies. All these boxes are usually manufactured from sheet steel that has been folded into shape and welded, though some of the equipment cases are made from aluminium alloy.
In addition to choosing the size of your box, it’s also important to pay attention to the lid size and to the box’s intended location on the vehicle. It has to suit your application. Many ammo boxes, for example, are tall and narrow with a removable lid at one of the narrow ends so, although their overall size is good, gaining access to anything stored inside can be difficult. You’ll only end up constantly spending your time pulling gear out to reach the stuff at the bottom. And while some ammo boxes have a lid with a hinge at one end and a securing clasp at the other, on others the lid is held by clasps at both ends, so it needs be completely removed to gain access to the interior. Less convenient for general storage, then. We chose a PA120, made to carry 32 rounds of 40mm grenades – the type used by the Heckler & Koch Grenade Machine Gun commonly fitted to the WMIK (Weapons Mount Installation Kit) Land Rovers used by the Royal Marines.  

The PA120 boxes are 18.76 x 10.39 x 6.36 inches (477 x 264 x 162 mm) with a capacity of about 14.8 litres and weighing around 5.9kg empty. To give you an idea of how strong they are, they are intended to be stacked up to 3 metres (10 ft) high and when fully loaded. This means the bottom ones withstand a load of up to 232 kg (511 lb) each! The markings on ours indicated they were US Army surplus, built in 2009 for carrying inert practice rounds. Our PA120 is narrow enough to fit comfortably on top of the wheelbox in the Defender load area, but big enough to have useful storage capacity. A drawback with this type of box is its lift-off lid, but we modified ours to a hinged opening. Check for splits or decay  on the rubber seals under the lids, which prevent water entering. Also look out for dents and rust, though a rub-down and coat of paint will hide superficial damage.


The ammo box can be modified and located on the vehicle to suit your own specific needs. The lid on our box was secured by two folding catch-plates, one at each end, and both needed to be released to open the lid. We wanted the lid to work on a hinge instead, so we locked the catch at one end of the box, then forced the lid open to the angle we wanted, intentionally bending the locating flange in the process. The catch on that end was then fixed in position by fitting a bolt through it into the box, secured on the inside by a wing nut (alternatively, it could be welded).

Securing the fixed end plate with a bolt means the lid is still easy to remove completely if required – giving the best of both access options. We used a carriage bolt, which has a square section under the head, and an M12 bolt just fitted the existing slot in the catchplate. The square engages with the slot and prevents the bolt from turning while the wing nut is tightened, and makes it difficult for a thief to turn the bolt from the outside in an attempt to open the box. Under the wing nut we fitted a Dowty-type sealing washer, which has a rubber insert and is squeezed into engagement with the screw thread when the nut is tightened.

Using this seal keeps water out but still allows us to take off the carriage bolt whenever we wish to remove the ammo box lid, and to refit it easily. At the other end of the box we fitted a spare eyebolt from an old four-point harness installation, with the eye poking through a slot in the catch of the box. This meant a padlock could be fitted through the eye to lock the lid. Because the eyebolt should never need to be removed, we applied a smear of silicone sealant to the eyebolt threads to keep water out, rather than utilise a Dowty seal. We used a Nyloc nut inside the box to secure the eyebolt so that even if a thief manages to force the eyebolt to turn from the outside, the nut will not loosen and the box will stay locked.

To secure the box to the bed of the Defender we’ve used six M10 machine screws which are screwed through from the inside of the ammo box. Again, Dowty-type sealing washers are used to prevent water ingress. At first we planned to fit a handle to the lid from parts used on the Land Rover Pulse ambulance. However, we decided that a full box would be too heavy to carry with one hand, so it was utterly pointless adding a carry handle on the lid. Besides the ammo boxes already have folding handles built in, so they can be carried two-handed.


www.surplusandoutdoors.com (ammo boxes)


CHOOSING YOUR BOX: Ammo boxes come in a wide range of shapes and sizes. This deep, narrow box opening on the narrow end is more difficult to load and unload.


This is the common M1A1 box. Quite small, though a group of them might be useful and they’re easy to carry, even when loaded.


The PA108 box for 50-calibre rounds, often known as the ‘fat 50’, is wider than the M1A1. It also has a hinged lid with a built-in carrying handle.


We’re using the bigger PA120 box, once US Army surplus. It fits neatly on top of the Defender wheelbox.


On our box the lid lifts off instead of being on a hinge, but there’s a solution for that which still allows the lid to be easily removed.

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