There are benefits and drawbacks for every method of securing your sporting arms or other valuables. For a considerable amount of money, you can buy nearly impregnable safes. I stress the word "nearly" here because every safe can be cracked, given the right knowledge and tools. Drawbacks to safes are many, including their expense and relative immobility. Another big consideration is that safes draw attention. The beefier they are, the more enticing they become. They are instant, albeit troublesome, targets.
At the other end of the spectrum we have the "hide it in plain site" school of thought. If you were to stuff $1,000 in a crumpled up Fritos bag and throw it on the floor, it isn't very secure, but it probably won't get a second look. This instructable is definitely more along the chips bag route, but not quite as greasy. I'm going to describe how a relatively cheap folding table can be turned into a firearms travel case. It doesn't draw much attention and isn't a top seller at the pawn shop, making it unlikely to be stolen in a burglary (which I hope you don't ever experience to begin with).
Disclaimer: I am not responsible for this being used to facilitate any crimes. I expect the reader to know all applicable laws and I will not be responsible should the information presented here be used illegally. I also accept no responsibility should your table-case or its contents be stolen. The item I described DOES NOT provide physical security, only concealment.
Step 1: Find a Plastic, Bi-Fold Table
You can get these at Wal-Mart for about $40, but I found them on Craigslist for $10 to $15. Given the purpose of our mission here, the grungier the better, which should knock some dollars off the asking price. Mine was left out in the rain with tools on it, so it's got rusted silhouettes of pliers and pry bars on the surface. I think I'll add some spray paint halos as well. The less attractive, the better.
Step 2: Remove the Legs
Yup, remove the legs. Find some other use for them if you like. Maybe you can bolt them onto a piece of scrap wood and then actually have a little table. I don't know. That's up to you. Whatever you do with them, consider making a follow-up instructable to share. Unless, that is, you just throw them away, in which case we all know how to do that.
Come to think of it, you could take one of these leg mechanisms and create a pretty cool folding slingshot frame! Maybe I'll do that. Awesome! I could mount it on my truck's roof rack and use it to launch water balloons!
Lay the opened table on the ground with the bottom side (i.e., not the table-top surface) facing up.
Select whatever item you're going to store in this case. Lay it flat on one side of the table. Here I used a little assault rifle thing, but you can use whatever you want.
With a marker, loosely trace around the entire item. Depending on how your table is molded, this will probably involve marking at several different elevations. You don't want your traced outline to be exactly the same as the actual item. I would suggest making each line about 1/4" farther out, meaning that in any one direction, your outline will be 1/2" wider than your object.
Step 4: Cut Out Your Outline
Now you're going to remove the interior part of your outlined shape. Depending on the thickness of the your table's plastic, you might get away with using a box cutter, but be extra careful if you go this route. I would recommend using a Dremel tool or some other rotary cutter.
The depth of your cut is important. I recommend measuring the thickness of the item you'll be storing and then adding 1/4" to 1/2" to that. Depending on how fancy you want to get, you can make your cut-out different depths in different places so that the resulting cavity will fit your object like a glove. This isn't necessary though. You can cut your cavity to a uniform depth and you'll be fine.
Whatever you do, don't cut all the way through the table!
Step 5: Line the Cut-Out
This is actually the most time consuming part, but you'll want to take your time so that the inside of your crappy-looking case actually looks nice.
For lining, I got a cheap yoga mat at Goodwill for $1.99. It's made of pretty rugged foam that is only 1/4" thick. I don't personally do yoga, but I can't imagine this would add much in the way of comfort. Nevertheless, it's perfect for our present purpose.
I can't really describe in detail how I managed this part. I did a lot of stuffing, un-stuffing, measuring, swearing, and cutting. Basically I would try to line the cavity with yoga mat and figure out by trial and error where I had to cut. I would fold here, snip there, tuck there until I got a pretty good fit. The hardest part is eliminating bulges here and there. I would compare the process to making a box from scratch. You have to figure out where to make the little flaps that will wrap around corners. If your cut-out cavity is box-like, this step will be relatively straightforward. If not, it'll be a challenge but definitely doable. Keep in mind that your liner doesn't necessarily have to be a single piece. Mine ended up in about three or four pieces.
Once you have your liner figured out and cut, take it out and cover one side with an epoxy. I used Liquid Nails, but I'm sure there are a ton of worthwhile alternatives, including silicone caulking. Once I squirted it onto the lining, I used an old paint brush to spread it around. In retrospect, it would have saved epoxy (and worked just as well) to have applied the Liquid Nails directly onto the interior surfaces of the cut-out where it would make contact with the lining.
I also wish, in hindsight, that I had taken some egg-crate type foam and crammed it into the hollow interior of the table so that it would puff out a bit, into the cut-out cavity. The lining could be glued to this as well, but more importantly, it would have created a better eventual fit for my object.
It isn't shown in the illustration, but I also glued a rectangle of yoga mat material on the opposite half of the table, so that my object would be cushioned on all sides when the case is closed.
Once the lining is glued in place, let it set for at least a day or two
Step 6: You're Done!
Make absolutely sure your glue is dry, lest you accidentally glue your object into the new case!
Now you just place your object in the cavity and close the case. Every table I've seen like this has some sort of pressure lock that keeps the case closed until you tug it open. I suppose you could put a hasp on it to install a padlock, but this might draw attention. Now just throw it in your trunk or garage and it'll never get a second look.