Be honest, you've got a zombie survival plan.

Even if you aren't one of those doomsday preppers, or a fan of The Walking Dead, you've had this discussion with friends or co-workers at some point. From barricading yourself into Wal-Mart, to making a break for your cabin in the woods where isolation will protect you from the shambling hordes, everyone has their own idea of what they'll do to avoid becoming the Monday special on the zombie buffet.

Most of the time, we agree on the broad strokes. However, the biggest source of disagreement in any survival plan seems to be our weapons of choice.

Some people will argue that a shotgun is the best weapon to fight zombies with, because the spread means it will do serious damage without pinpoint precision. Other people argue that small-caliber weapons are better because they're quieter and provide you better accuracy. And then there's the contingent that argues for a machete, a hammer, or a spear, because melee weapons never run out of ammo.

If you're not a gun nut, though, you might have missed one of the most ideal weapons for any apocalypse-style scenario; the Medusa Model 47.

If you know anything about guns, it's that every gun is specifically meant to fire a single kind of round. You can't take a .38 revolver round, fit it into your 9-millimeter semi-automatic, and just start shooting. If the bullet doesn't match the gun, then you can't pair them together. Period.

Unless you manage to get your hands on a Medusa, that is.

As you can see from the video, the Model 47 looks like your average, short-barreled revolver. It fits the hand, it's got a comfortable grip, and it's an aggressive little piece of work. What makes it unusual is the fact that it can take a variety of different rounds, and fire them all as if it was made for them.

Because it was.

Unlike your average revolver, the Model 47 has a unique retaining mechanism that allows it to fire several different calibers that are all similarly sized. Within the cylinder, there is a clip that holds bullets in place. This is why it's possible to chamber a .38 special, a .357 magnum, two 9 millimeter rounds, and a standard .38, and fire all of them without any problem.

This mechanism was invented by Jonathan Phillips, who was a computer engineer for NASA in addition to being a gunsmith, competition shooter, and co-founder of Phillips & Rogers, according to Popular Mechanics. Phillips would regularly carry half a dozen guns to the range when he would go to shoot, and it struck him that most of the guns he was hauling around used shells that were comparably sized. So why not make one gun that would fire all of them, and do so with great accuracy?

So that's what he did, and it worked so well the weapon eventually made its way onto the open market.

What's In Your Bug-Out Bag?

Not all apocalypses are created equal...

Despite how unique it is as a gun, the Medusa never really caught on. While it was popular with survivalists, lovers of unusual weapons, and those who appreciated only having to carry one gun to the range, the Model 47 became something of a niche item. Nowadays it's a collector's piece, but there is still interest in what makes it so unique.

After all, if you're digging through ruined cities while playing the real-life version of Resident Evil, you want to make sure you can use as many of the bullets you find as possible.