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Hypothetical Liquid-filled Projectile

02 Sep 2017
@ 06:52 am (GMT)

Sean Hobin

Hello everyone - I am writing a science fiction story, and one of the elements of the story involves one character shooting another at long range with a liquid filled projectile. This forum seems like the kind of place that might be able help me work out the details of how this would work...

The mission of the shooting character is for him to get the liquid filling of the projectile onto the skin of the target character, and/or possibly into their bloodstream. However, this shooting is not meant to be fatal, so the target should not be mortally wounded. I was hoping to be able to have this projectile shot from a decently long range - perhaps a quarter mile.

I understand that these requirements are quite specific and possibly impossible, but I was hoping for some assistance in coming up with a technically feasible way for the character to accomplish this feat. Must the projectile be metal? Perhaps a type of plastic or ceramic (brittle, I know) could be used? I will add that it is totally okay for the victim character to be injured, even gravely, just so long as they survive.

Hypothetical gun and bullet stats:
Projectile must be fillable with liquid
Temperature of liquid inside projectile cannot exceed 100 degrees Fahrenheit (liquid surrounded by heat-resistant shell?)
Projectile cannot be lethal, but may be severely damaging (shoot for extremities?)
Gun is preferably some type of rifle that can fire from stealth, ~1/4 mile from a target
Gun should be silenced - the shooting character hopes to hit his target and get away

Any help would be greatly, greatly appreciated!


02 Sep 2017
@ 08:49 am (GMT)

Nathan Foster

Re: Hypothetical Liquid-filled Projectile
Hi Sean, normally I do this type of work privately (see consultation tab) just so that the author can hash out ideas but also learn without feeling exposed. But if you wish to have wider input, that's fine.

One thing you must understand is that any bullet traveling above the speed of sound creates a supersonic crack. You cannot silence a projectile unless it starts out very slowly (such as black powder era guns and some of the new special forces chamberings designed for close quarters). The trouble is, the load you want to shoot is light (water is lighter than lead) so it needs to start out very fast. Range is the key to stealth, not silence. Actually in reality, the louder the shot, the more it confuses humans and game alike.

Ideally, the cartridge would be akin to the 577 Snider in size but possibly wider still. The bullet would consist of a heat shielded sabot. The sabot would be made of possibly two materials, one to allow it to swage to rifling of the bore, the other as a heat shield. The actual projectile would be within the sabot. The projectile would need to be made from a polymer or epoxy combined with powdered steel. The nose (ogive section) would have to be very weak and break up on impact, exposing a blunt profile (apart from a pipette tip) to arrest any further penetration.

The bullet weight with liquid would only be around 50 grains which in the world of ballistics is very light and can be difficult to deliver over a great distance due to wind drift issues. At 70 grains bullet weight, there would be a risk of serious injury but this would possibly be a better weight for exterior ballistics. Muzzle velocities may have to be up around 3000fps for optimal reach.

But there are many ifs buts and maybes. Others can chime in here and have their say. I had a biologist wanting help with a very basic nylon projectile a couple of years back, but this was somewhat easier to conceptualize as the intended range was only around 100-150 yards, a basic extension of the dart gun.

Of course, all of this is based on our current (lack of) understanding of physics and our approach to gravity, always fighting it but never truly overcoming it. An anti gravity drone the size of a hockey puck could deliver a dart with a great deal of stealth.

A particle weapon would be tricky because the greater the range, the wider the beam but with the right tech, it could be used to change cell / protein behavior.

But then, do things always have to make sense for us to be able to enjoy them.

02 Sep 2017
@ 02:08 pm (GMT)

Lane Salvato

Re: Hypothetical Liquid-filled Projectile
OK well if this is science fiction, I can contribute at least an idea. The projectile comes apart with the friction of the air and disintegrates feet from the target. This is the trick, getting to the correct distance without being detected, and is the limitation of this particular technology. The projectile is 35 caliber, which is moving somewhat slowly compared to traditional military rounds.

The liquid isn't a solid mass of liquid but is contained in tiny spheres that come apart when contacting clothing. The liquid has nearly no viscosity and enters the skin and blood stream, causing severe bruising but no serious damage. The liquid is so lethal that only a fraction of a milliliter is required.
02 Sep 2017
@ 02:36 pm (GMT)

Mike Davis

Re: Hypothetical Liquid-filled Projectile
"ice ice baby"

a frozen projectile in a theres a concept.....
the liquid would get delivered and no projectile to engrave rifling on to leave clues to shooters identity.
250mtrs makes it harder to achieve,50mtrs is piece of cake...think rocksalt load in .12ga shotgun.....
heck any old paintball gun would do it at 50 yards........just have to beef up the whole shebang...maybe up scale it till you shooting a golfball sized projectile with a skin as soft as you can keep it...spudgun.
what a hoot to think of this concept.
02 Sep 2017
@ 07:16 pm (GMT)

Warwick Marflitt

Re: Hypothetical Liquid-filled Projectile
A silent slow speed drone projectile like a thistle seed with jellyfish or stinging nettle like spikes that administer the serum when the target unwittingly brushes it away! Or a fine powder/gas delivered by a mortar round Bursting nearby and the cloud/mist of serum Surrounding the target. Its fantasy so the fine details or believability don't really matter. ..... its a bullshit story so why worry about the detail. ...... a powder fired into rain clouds and the falling rain delivers the evil zombie apocalypse plague. ........easy to do its all been done before read history for how.
08 Sep 2017
@ 09:11 am (GMT)

Sean Hobin

Re: Hypothetical Liquid-filled Projectile
Wow everyone - thank you so much for your feedback! It is incredibly helpful. Nathan, I will keep your consultation tab in mind - that could be a great option for me in the future.

Your point about the loudness of the shot in particular probably has story implications I hadn't previously considered, and is well taken.

The detail about the two-material, heat-shielded sabot is very helpful, and makes sense. I am still a total newbie to this stuff, so I actually had to Google sabot and swage, but I now understand what you are saying, and it seems like a perfectly logical system for our fictional character's needs.

But then, do things always have to make sense for us to be able to enjoy them.

Understood! But my hope is that I can write something realistic enough that even you hardcore ballistics aficionados will be able to suspend disbelief and enjoy the story. I know that when someone gets something wrong with bacteria or viruses in a story, it totally breaks my immersion (I am a microbiologist).

Lane Salvato: I really like your idea of the projectile bursting immediately before impact! Perhaps the projectile could be very large, and possess a second stage that would burst when a few feet from the target? It would function closer to a missile than a bullet, but hey, as you say, this is sci-fi :)

Mike Davis: Great idea! I hadn't considered freezing the liquid, but this could potentially work. I will explore this idea further.

Warwick Marflitt: Wow - love the idea of the drone delivery. It made me realize there are many types of drone delivery I could consider...I could even have a drone with a liquid bomb payload hone in on the target and explode once it reaches them. In fact, the usage of drones is very likely in this near-future sci-fi scenario.

Thanks again everyone - you were incredibly helpful, and I hope whichever idea I end up using does your great suggestions justice.

08 Sep 2017
@ 05:08 pm (GMT)

Greg Quick

Re: Hypothetical Liquid-filled Projectile
Hi Sean. Well since this is sci-fi then you could think of all sorts of neat ideas that could theoretically be feaseable in the future(or even near future). The first thing I think of when it comes to sci-fi silent rifles I immediately think of electromagnetic "rail" guns. Silent, no bang bang gun powder and keep the velocities low enough so it doesn't break sound barrier. So in order for that to be believable you'll need to make the projectile that's designed to "sail" through the air at lower speeds but remain accurate. If it's a liquid that you're after, why not let it be a metal projectile encasing(because it's coming out of a electromagnetic rifle) a liquid capsule that's the shape of the bullet. Once the bullet has reduced velocity enough for the liquid bullet to survive air resistance the outer metal projectile would peel off and all that's left in the air is a hardened aerodynamic case filled with the liquid with just enough hardness to penetrate human skin but disengrates once it hits muscle or bone. Hmmm maybe I'll write a book. Haha Just kidding. Hope these ideas help.


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