Passing explosives off as a gun

Depending on how big of an explosion you need, you could mill out a gun (if it's a pistol) and pack it with explosives, or if it's a semi-auto style (pistol) remove the barrel and mill out the slide. The detonator would require some space, but I don't see why a triggering device as part of the gun couldn't be constructed.
If you're talking an assault rifle style gun like an AR, there's all kinds of room for explosive. You could pack the handgrips, upper reciever and stock with plastic and rig a detonater into the lower receiver so that when you pulled the trigger it explodes.

You know, if he doesn't see this you should PM JAR (jamesaritchie) he knows a lot about guns and could probably tell you whatever you needed to know.

I'm not sure if I correctly understand the question.

A . Are you talking about taking a lump of plastique and forming it into a shape that resembles a gun hoping to fool someone into thinking it is a gun?

B. Or, are you talking about sabotaging a gun (with plastic explosive) so it will explode when someone shoots it?

If you mean option A, plastic explosive is a lot like modeling clay. You could form it in the shape of a gun, and even paint it, but it will be very, very obvious that it's a hunk of (essentially) clay in a gun shape. (Unless the viewer is at a distance and all the say is a "gun shape")

If you want to take a real gun and rig it to explode there are many simplier ways then modifying it with plastic explosives. Simply blocking the barrel with packed in dirt (think big blockage, a couple inches of thick dirt or more) would be enough to blow the barrel up. That would destroy the guns ability to fire and would likely injury (and possibly even kill) the shooter. It's not fancy, or reliable in that too small a blockage might be shot out instead of blowing up the gun, but it's simple. All the person would have to do is shove the barrel in some somewhat soft earth to pack the barrel with dirt. If the shooter is not killed, or seriously injured, at the very least they'd be very distracted when the barrel bursts when they fire the gun. (Assuming there was enough dirt in the barrel)

If you want something fancier, and more realistic (in my opinion)than taking a gun apart and putting plastic explosives in the grips, etc, you could have a character sabotage the ammo.

In Vietnam U.S. Special Forces ran a secret program where they modified the types of ammo used by North Vietnam and the Viet Cong (rifle and machine gun ammo and mortar shells) by removing the propellant (gunpowder) and substiting plastic explosive. They'd carefully reassemble the ammo and even put the sabotaged rounds back in the ammo crates and seal them so they didn't look like they'd been opened.

The Special Forces would take some of this sabotaged ammo with them on missions and, when they found enemy supplies, they would add this sabotaged ammo to the enemy's supplies of ammo they found. The idea was the enemy would not realize the ammo was sabotaged and distribute it to their troops. The sabotaged ammo would explode when fired, injuring or killing the shooter, and it would hurt the morale of the enemy and make them not trust their own ammo supplies.

The reports I've read indicate it worked pretty well.

So, for your story, you could have the character who is sabotaging the gun sabotage the ammo instead. All they would have to do is have access to the ammo, have some tools to pull the bullet out of the cartridge case (in a pinch pliers or a multi-tool would work) dump the propellent, and substitute a small amount of plastic explosive in it's place. They could use pliers to force the bullet back into the cartridge to put it back together. (If they have access to better, more specialized ammo reloading tools, the switch would not be noticeable. If they used pliers, or a multi tool, a close inspection of the cartridge would show plier marks, etc. But, who is going to pull the ammo of the magazine to look for plier marks, etc)

They would then have to arrange for the doctored ammo to be placed in the gun of the person they want to sabotage. (Lot's of ways to do that. They could "surrender" the gun to the character, or load the gun for them, whatever works best for the story)

If the character who is sabotaging the gun knows how to pull apart a cartridge (not hard), and knows this trick (it is part of military lore), and has access to a small amount of plastic explosives, some pliers or a multi tool, and the ammo, they could sabotage a few rounds in just a few minutes.

If I had access to the other person's gear and wanted to do this I'd try to sabotage enough rounds so that the first round in ALL there mags was rigged to blow. That way, no matter what mag they put in the gun, it would blow. And, if I had to use their gun, i'd know to eject the first round and the other rounds would be OK to shoot.

Or they could just do this to a random round in the mag so it would be a surprise somehwere down the line. (That's how the Special Force did it. They never booby trapped the first round and varied how many rounds in the mag down they went those times taht they sabotaged rounds in a mag instead of ammo in packages).

Edit: Two thing I thought I should add.

1. Any barrel blockage can blow up a gun. Dirt, concrete poured in the barrel and allowed to harden, heck, in the right circumstances, spider nests have been known to blow up a barrel. The gun is not fireable afterwards, but, as I mentioned, the shooter may or may not be seriously injured or killed.

2. From what I've read, the sabotaged rifle and MG rounds in Vietnam DID usually kill or at least seriously injury the shooter. The detonation from the plastic explosive in the cartridge created a larger, more powerful explosion than that caused by a simple blockage in the barrel. The receiver of the gun would blow up and essentially become shrapneal and since a rifle is usually held against your face when it is fired, you can see how this would kill or seriously injure the shooter.

Ok, just molding it out of plastic explosives wouldn't work. Think about plastic explosives as a lot like Play Dough (well, explosive Play Dough anyway...). A sculpter could mold a pretty realistic gun out of Play Dough, and paint it, but when you picked it up you'd tell "That's just not right..." (Heck, when you looked it you could likely tell)

As far as "removing the core of a gun.." eh, it might work... Guns are machined from steel, or use stamped steel, and sometimes use plastic for non-stressed parts (lower assembly, grips, pistol frame, etc). There are some parts that could simply be removed and replaced with explosive, but then the gun could not be actually loaded or even be able to have the action cycled.

If you want to go that route in a pistol they could remove the barrel and pack the inside of the slide (where the barrel goes) with explosives and then have the cut off stub at the barrel at the end poke out still it still looks right. The metal slide would provide the shrapnel when it explodes. They could also pack ball bearings in with the explosive for more shrapneal. (Or simply keep the barrel in and put explosives both in and around the barrel).

I suppose you could also fill the magazine (where the loaded cartridges usually go) with explosives by taking out the spring and other parts and cramming the explosives into the now hollow magazine shell. If the gun was a gun with a plastic frame, like a Glock, the plastic wouldn't provide as much shrapnel. Even in a metal framed gun I don't know if thered by enough metal to create enough shrapneal to wound anyone but the shooter.

As Expresso mentioned, in a rifle you could remove the stocks and handguard, hollow them out (if they aren't already hollow - many are) and pack them full of explosives and even small metal bits (like large BB's) to create shrapneal. That would give you a larger explosion with more shrapneal.

You could also pack the barrel with plastic explosive and rig the detonator to go off when the trigger is pulled. That would be doable, The barrel would provide the shrapnel, but again, probably only enough to injure or kill the shooter and maybe a person or two standing right next to them. (You could do the same thing with a handgun).

Making it so the bomb would be armed when the safety is turned off and then it explodes when she releases pressure on the grip would actually be very tricky. There is not normally anything pressure sensitive in the grip so they'd have to add a pressure sensitive triggering device and rig it to go off when the pressure is released. That would take up room and take away from the room available to pack in explosives.

Also, if she's really unfamiliar with guns, what makes you think she'd know where the safety is and how to operate it. Some go up for "Fire", some go down for "Fire" and there are many accounts of criminals getting guns from cops and not being able to figure out how to take off the safety to shoot them.

Another issue is creating a big enough blast with enough shrapneal to kill or injure more than just the shooter and maybe one or two people. You need room for enough explosives and shrapneal and there isn't just that much room in a handgun. Plus, much of the explosion would be absorbed by the person holding the gun. Their body would take the most damage and shield many of the other people from much of the shrapneal and blast. It would be more likely to get a big enough bang from a rifle, since there is more room to pack explosives, then a pistol.

The biggest problem I have with the idea isn't from a purely technical point of view. To be honest, yes, you could figure out the mechanics of rigging a firearm with explosives so it is technically feasible. The thing is, the whole idea the way you have expressed it seems very much like a cheezy, over-complicated "super villian death trap" kind of thing.

Who would take all that advance time and prep, and go to all that work, to rig a gun to explode to kill a bunch of people and then laso have arrange everything so EXACTLY the right person, at exactly the right time, has access to the gun and will set off the gun bomb? It seems like a lot of work for a not tottaly reliable way of killing someone. In my opinion, that stretches the suspension of disbelief to breaking.

At least the "blocking the barrel with dirt or another object" is a known hazard and could be done simply and even "substituting plastic explosive for the propellent (gunpowder) in the ammo" is a historic "dirty trick" that was done by the military in real life to sabotage the enemy's ammo.

Could you set up the scenario a little bit more so I understand why you want a booby trapped gun? That might help me understand how feasible it might be or give me an idea for an alternative.

If you wanted to kill people around the character, I think you have to go with a bigger gun. If you use a full sized AR style gun, or an old school M16, there's plenty of room for explosive. You could use A-2 plastic foregrips, which are mostly hollow, and even cut out the barrel in that section to pack in more explosive. You could remove the bolt carrier and pack the upper reciever. You could remove the buffer tube and even hollow out the rest of the butt stock. A hand grenade uses 6 and a half ounces of an explosive called composition B (RDX+TNT), which is similar to composition C (mostly RDX), or C4. You can imagine the size of a hand grenade, and get a rough idea of the size of the explosion you would be dealing with (go to youtube and type in hand grenade explosion). As Trebor said, you would probably want to mix in some ball bearings or something so you have more than the concussive effect and parts of the rifle doing damage.
You would need to make sure all the parts are linked, to ensure they all go off.
You could probably arm it to explode using the safety, but the pressure sensitive hand grip might be tricky. You could put it on a time delay if this would work.
They do make pressure senstive switches for hand grips or thereabouts (some can be put wherever the shooter wants) that trigger lights and lasers. These generally require a concentrated pressure, so they're not inadvertently switched on. For the purposes of a fiction story, though, maybe a tech expert could rig something.

Isn't the Uzi come with a standard grip safety which is great for triggering the explosion? It can't pack as much explosive as a rifle but still more than a handgun.

Bing Zabriskie said:

Isn't the Uzi come with a standard grip safety which is great for triggering the explosion? It can't pack as much explosive as a rifle but still more than a handgun.

Click to expand...

Yeah, but hand a non shooter an UZI and they won't even know to squeeze the grip safety.

Trust me, I know. I have an UZI and have shown many people how to shoot it. Even shooters don't always get they have to squeeze the grip safety until you show them.

A rifle would be pretty tough to fit in a computer bag. (No way you'd hide it under a sweater)

You can get an AK with a folding wire stock. That would reduce the size of the rifle, but you wouldn't have the stock to fill with explosives though as it's just a metal wire or simple stamped metal stock.

If the gun doesn't have to meet legal requirements there are short barreled versions of the AK (and AR-15) that would be shorter overall.

Still though, I don't think you'll get a AK or AR into a laptop bag, even with a folded stock and short barrel. By the time you cut it down enough you essentially have a large handgun, which gives you less room for the explosives.

Now, if you switch it to a UZI or similiar submachine gun, you might be able to fit it in a laptop bag. With the short barrel and folded stock it's smaller than a rifle.

Here's a question: Does it have to be the GUN that is rigged to explode? If she's smuggling it in in a computer bag, maybe instead she could also be given a laptop in a bag to use to deliver the demands (or for whatever reason, maybe the laptop is a prop to get her in because everyone has a laptop). The bomb could be in the laptop.

Or, maybe she's given what she is told is a "bullet proof vest" to wear under her clothes and a handgun. (The handgun is easier to hide and might be disabled not to fire, but she doesn't know that).

The "bullet proof vest" she is given could really be an explosive vest of the type used by suicide bombers. A vest rigged with plastic explosives and ball bearings. The person who gave it to her could have it rigged for remote detonation or on a timer. It could also be rigged for "anti tampering" to go off if she tries to take it off or someone tries to disarm it. (Defeating those devices could be a plot point).

The reason I said to have them tell her it was a bullet proof vest is to give her a reason to put it on in the first place, and to give her a reason to not question why it is a bit bulky and heavy. She doesn't know better so she'd just figure that's what a bullet proof vest is like.

Unfortunately, as events have shown, you can pack enough explosives and ball bearings (for shrapneal) into a vest that can be concealed under clothes to kill many people in close proximity.

Btw, just as general advice, it might be helpful to find someone you know who shoots or go to a gun range and rent a gun or two sometime. You don't have to be an firearms expert, but a little practical knowledge goes a long way. Handle an AK and an AR-15 and a few handguns and you'll have a much better idea of how big they are, how heavy they are, how easy (or hard) they would be to hide, etc. Heck, if you go a gunshop and ask someone to show you how to take apart (field strip) a pistol, say a Glock, it is very likely they will. (Unless they are really busy).