DIY Lockable Ammo Case

About: I am a fourth year Architecture student who is interested in art, design and engineering. I am always looking for new projects and new ways to build things, and always enjoy Instructables because it is a gr...

Hello Instructables!

This is just a simple build using an old .50 cal ammo case and a combination trigger lock.  I built it to keep all of our ammunition safe while we are in the woods.  It is a quick project, only taking about 30 minutes excluding drying time.

This is not my design, I originally saw this done at the Burlington Rifle and Revolver Club (BRRC), and they used it to store all of the .22 ammunition for youth target practice on Saturdays.  I like the design because it is simple and uses pre-made and easily available parts.  It is a safe and secure way to store ammunition at home or on the go and is very convenient because you never have to worry about loosing your keys!

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Step 1: Materials

You will need:
  • an ammo case
  • a trigger lock
  • a drill and drill bits
  • pliers
  • an x-acto knife
  • metal files
  • masking tape
  • lots of epoxy
Optional: Spray Paint

Step 2: Drilling

This is the easiest part of this build.  I used a 1/2" drill bit, after pre-drilling with several smaller bits, to create a hole for the trigger lock to fit through.  I filed the rough edges smooth and widened out the hole just a bit so there was more clearance.

Step 3: Pre-Glueing Prep

Firstly, remove any rubber pieces that are loosely attached to the insides of your trigger lock.  These will prevent the epoxy from solidly bonding the lock to the case, which is important because you cannot hold the back end of the lock in place while the case is closed.

After any loosed parts are gone, mask off all the moving parts.  it is important to cover any gaps because if epoxy can seep into the mechanics of the lock it will be permanently disabled.  

Step 4: Gluing

Time to use up nearly half a syringe of epoxy!  I placed a lip of masking tape along the bottom of the trigger lock to keep the epoxy from dripping while I placed it in the hole, and then filled the areas that would be in contact with the case with epoxy.  After the trigger lock was in place I added more epoxy around the edges to seal it on completely and held it in place until everything dried.  Probably a good idea to use 5 minute epoxy instead of the slow drying stuff.

Step 5: Making More Clearance

After the epoxy had set, I removed the masking tape and tested the fit.  Unfortunately, the lock was slightly to the right of the hole I had drilled.  So I grabbed some metal files and widened the hole until the lock fit.

Step 6: Painting

Now that everything fit together, I painted the lid of the case blaze orange so that it cant get lost in the woods.

Thanks for reading my instructable, hopefully it comes in handy!

Step 7: Update

After a bit of use, the epoxy eventually gave in and broke off. If the case is already locked it is still secure, because the lock is still held together, however this makes it impossible to use the case after removing the lock because it is impossible to hold the back end of the lock in place inside of the box while locking.

So I gave up on epoxy, and decided to make something a little sturdier.

Unfortunately I didn't take any photos while making the repair, but it's pretty simple. I drilled two holes in the tin and two holes in the backing part of the lock, making sure not to damage the mechanism. I drilled the holes so that they were aligned, and then all you have to do is use two nuts and bolts to fasten the lock more permanently to the can. If you wanted to make it as secure as possible, you could use red loktite on the treads or , if you used steel hardware, you could weld the front and back end of each bolt to keep it from going anywhere. I personally just left the hardware bare, and so far no more issues.

Hope that this fixes any problems!

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    8 Discussions


    5 years ago on Introduction

    So only some wad of epoxy holds the lock in place on the inside ? Could not a person of questionable character just whack it with a hammer and get it open ?

    2 replies

    They could break the lock off from the inside, but the lock will still hold the case closed. The pin of the trigger lock is still in place, so the lock is still perfectly functional. However, when you open your lock again the back of the lock will fall off into the inside of the box, because it is no longer attached. It just means that you will have to repair it before you can lock it again.


    5 years ago on Introduction

    That would be a great Geocache. You could give the digits as the hint. If I ever make a Geocache I will make one in an ammo can like that. Thank you for those quality pictures.


    5 years ago

    Generally the slower the epoxy the stronger it is.

    1 reply

    I used 5 minute epoxy just so that I didn't need to hold the lock in place very long. But if you wanted to have a stronger bond then yes, slower epoxy would be better.


    5 years ago

    great instructable. I was wondering if you had to prime it.

    1 reply

    I just used some orange Krylon spraypaint. The surface of my ammo box was already really rough, it had a matte paintjob over the original. If your box is completely smooth you may want to prime it first.