High-explosive handgun

Sizzles · #1 12-21-2012, 05:04 AM

Has anyone ever produced a gun (rifle/handgun) which used a high-explosive instead of powder ?

Martini Enfield · #2 12-21-2012, 05:55 AM

The closest I'm aware of are the Gyrojet guns (including a pistol), which used rockets.

Yes, a handgun that fired rockets. Unsurprisingly, it made an appearance in You Only Live Twice; doubtless because it was exactly the sort of thing that belonged in a James Bond Movie.

The design was not a success for a variety of reasons including technical limitations and the obscene cost of ammunition.

Francis Vaughan · #3 12-21-2012, 06:14 AM

You probably would never want to use a high explosive. It is all downside, and no upside. A high explosive, despite the name, and popular reputation, isn't a more powerful explosive, but one that detonates with a shockwave travelling through the exploding material at a supersonic rate (supersonic relative to the speed of sound in the exploding material that is.). For a gun of any sort, detonation is bad for much the same reason you don't want detonation in a piston engine. You want a sustained release of energy that transfers the maximum energy to the projectile over the length of the barrel, not a jarring release that slams the projectile (and therefore the gun proper) and then stops before it has travelled very far. High explosives are good for fracturing and breaking things, but they are not good for moving things. You want an explosive that moves the projectile with maximum efficiency, not one that is good at fracturing your gun.

Cheesesteak · #4 12-21-2012, 06:29 AM

I did look up energy density, and most high explosives have a better energy density than gunpowder, from 50% to 100+% more energy per kg. The benefit you would get out of this is slightly smaller cartridges. Given the downsides of HEs, what you really want is a higher energy density gunpowder, that will let you reduce cartridge size and maintain the performance.

solosam · #5 12-21-2012, 06:49 AM

It doesn't matter. We want a consistent and predictable burn rate. Explosives aren't very good at creating those.

Besides the internal ballistic factors, you have to think about the integrity of the casing. A sudden explosion would cause the casing walls to bulge or crack. This would cause a failure to eject. Ammo prices would go up because you couldn't re-use the casings. The solution would be to increase the strength and thickness of the casings... which would just make them bigger and more expensive.

Nevermind the danger of the explosive shockwave detonating the other rounds in your magazine. This, of course, would depend on the nature of the explosive you're using, but would be profoundly unpleasant.

Hail Ants · #6 12-21-2012, 10:49 PM

Quote:

Originally Posted by Sizzles

Has anyone ever produced a gun (rifle/handgun) which used a high-explosive instead of powder ?

Well, definitions vary, but 20^th century long arm cartridge powder (i.e. gun cotton) kind of is a high explosive. Much more so than black powder, it's based on nitro-glycerine.

Stranger On A Train · #7 12-23-2012, 12:24 PM

Quote:

Originally Posted by Hail Ants

Well, definitions vary, but 20^th century long arm cartridge powder (i.e. gun cotton) kind of is a high explosive. Much more so than black powder, it's based on nitro-glycerine.

While it is true that many smokeless powders and cast propellants use high explosive compounds such as nitroglycerine, nitroguanidine, RDX, HMX, et cetera, to obtain higher combustion rate and energy, the loading is controlled specifically to prevent transition to a detonation state. The problem with detonation, as previously mentioned, is both that it is extremely stressing on a mechanism that has to perform repeated functioning, and that the resulting pressure curve is difficult to replicate and will cause instabilities in the performance of the device. Anyone familiar with pyroshock testing (where an explosive charge is used to provide a high frequency shock input to a unit being tested) is quite aware of the variability of shock levels resulting from pyrotechnic charges, but it is the only way to obtain certain shock spectra.

Detonation or detonation-like shocks in liquid rocket engines during the ignition transient was and is a significant design problem that will cause spontaneous self-disassembly of the propulsion systems. Solid rocket motors, although often loaded with a propellant mixture that contains a certain amount of high explosive, are designed to specifically avoid getting anywhere close to a detonation state, and in general will not undergo full detonation short of initiating this by using a large quantity of explosive charges (sometimes done to destroy or "demil" retired motors). However, very high speed impact, or transition to detonation due to a crack in the propellant grain can cause a propellant grain to detonate with yields approaching or even exceeding 100% TNT by weight.

Stranger

dstarfire · #8 12-23-2012, 04:30 PM

Quote:

Originally Posted by Stranger On A Train

the loading is controlled specifically to prevent transition to a detonation state. Stranger

So, how does HE add to the propulsive power if it doesn't detonate? I know explosives can burn without detonating, but what would be the benefit of that over an equal amount of smokeless powder (or whatever other propellant is being used)?

Stranger On A Train · #9 12-23-2012, 07:55 PM

Quote:

Originally Posted by dstarfire

So, how does HE add to the propulsive power if it doesn't detonate? I know explosives can burn without detonating, but what would be the benefit of that over an equal amount of smokeless powder (or whatever other propellant is being used)?

(High) explosives are just very energetic explosives that also have a tendency to detonate; that is, to propagate a chemical reaction that progresses in excess of the speed of sound in that material. However, even at conditions that will not support detonation the material will still combust very energetically, and as (most) explosives contain or break down into oxidant and reductant, there is no variability in their output due to variations in mixing. So the biggest advantage for flake propellants used in small arms is really consistency in combustion rather than the increase output yield, although it does allow you to get more energy out of a given cartridge size. For larger cast propellants, the increase in yield of combustion energy is significant, but also comes with the problem that not only is it assigned a higher hazard classification number, but if stored or transported with other propellants they are also treated as being the higher classification for the purposes of quantity-distance (QD) calculations regardless of composition.

Also, I would personally not want to carry a magazine of cartridges that may detonate in a pouch on my hip. Small arms bullets, if inadvertantly ignited (say, by being thrown into a fire) will pop open and make a loud bang, but the velocity imparted on the bullet will be minimal owing to the lack of containment and alignment. An unconfined high explosive, on the other hand, will create shrapnel and blast effects that would be highly undesirable.

Stranger