# How to prevent guns from working?

I'm writing a story where some agents are sent to a small town in the 80s and must work out what is going on there. However, there are no guns in the town and to prevent the agents from having an overwhelming advantage against the local people, I want to create a condition, mechanism or phenomenon that could stop guns from working. I will set some conditions about the scenario:

• The story takes place in the 1980s, so the technology involved must (at least mostly) fit that era.
• It is a small town, so while I could add some rich secret organization (because the plot is in its early stages), cheaper ways to deal with guns would be better.
• Preventing guns from working in the entire town would be perfect, but if this is not possible, preventing them from working just in closed spaces would be fine too.
• I'd like it to be as hard as possible for readers to find out how the method works.
• The point about guns not working is not a plot twist (but its cause could be) and it is well known by local people, but not by people from outside.
• The agents are common police officers and they didn't know about the gun problem until they attempted to use them.
• Is it a plot point that guns dont work here? What sorts of agents are these? Federal? Are they undercover? We need more details. As it stands, the simplest solution is for the town to just be a "Gun Free Town" and the agents are forced to surrender their firearms to the local sheriff. Its even better if the agents are undercover because then they must give up the firearms, or else blow their cover. May 12 at 4:03
• If you don't want the readers to find out how it works, Gravity Falls it. Someone discovered something back in the 50s and kept it to themselves, in total violation of most of the laws of physics. May 12 at 4:12
• What's stopping your agents from messing up and having their guns stolen by a racoon or something similar? Sounds a lot more believable that a space-time anomaly that magically disrupts the chemistry/physics of firearms. And what's preventing the townspeople from using blow guns? Or bows? Or crossbows? Or any other kind of long ranged weapon? All of those existed and all can still be pretty deadly, especially if the projectile's tip is laced with poison or fecal mater May 12 at 15:11
• A gun only provides an "overwhelming advantage" when you are already in a fight and are prepared to use lethal force. FBI agents (or whatever) visiting a small town "to work out what is going on" probably don't march in guns blazing. Unless you have some idea how these guns would logically come into play, the obvious solution is just not to bring them up at all. How many times in this plot does Agent Doe engage in a firefight with a clear shot at an obvious bad guy? I feel like this question presumes so much about the setting that it's impossible to answer without more context. May 12 at 15:20
• This is a duplicate, but the other question is a couple of years old. The problem is that guns are purely chemical/mechanical (no hocus pocus super electronics) and very well understood. For them "not to work" would mean breaking seriously fundamental laws of physics. May 13 at 7:38

Frame challenge - sabotage

As stated, there are no firearms in the town, so the only firearms that need to be neutralised are those that the police officers bring in themselves. Separate the agents from their firearms - while they are in the shower, or swimming, or doing a gym workout or mandatory-welcome-to-the-town sweat lodge - and sabotage them. Whoever is responsible for this practice has a firm anti-guns agenda which may be totally unrelated to whatever other plots are going on in town.

Regarding the preferred low-detectability method to sabotage the firearms, this will vary depending on what type the agents are carrying. For plot purposes I would suggest that the agents are only carrying semi-automatic pistols (eg Colt M1911, Browning Hi-Power, Beretta M92 or similar). The saboteurs remove the firing pin and rapidly file it down (or replace it with a prepared filed-down firing pin, though they would need to know the model in advance). Standard daily cleaning for most people would not involve removing and inspecting the firing pin (normally just separate the slide from the handgrip, remove and clean the barrel and oil the action) so the sabotage will not be detected until the agent attempts to fire. The average police officer will not be carrying a spare firing pin, so their handgun is a useless chunk of metal until they can get a replacement.

How and why someone has such a firm aversion to firearms is a story-based question, but given the number of firearms-related fatalities that occur it should be easy to create motivation for an actor.

As o.m. stated, if there were a magic technology that could neutralise firearms then it would be in use - the police would deploy it every time there's a siege situation involving firearms! Short of technomagic far beyond the 1980s level involving primer-eating nanites or mysterious energy fields imposing energy thresholds there is nothing that can stop the trigger >> hammer >> firing pin >> primer >> powder >> speeding bullet sequence of events without sabotaging the mechanism involved. (Note that the mysterious energy fields will probably also stop vehicles, power tools and possibly essential biological processes.)

• I like this one, but can't it be much easier? Common agents can't just walk in into any town and do their thing. They might have to submit to the law enforcers of the town, which both has a place to house the weapons off duty and possibly sleeping quarters. Many countries don't allow police to take their weapons home, or won't allow it without proper storage. In a different town proper storage can be difficult. The saboteur could just hate guns. Maybe accidentally killed someone in the past. Also a town can simply not have guns. Culture related. It's not really a frame challenge imho. May 12 at 6:31
• @Trioxidane apologies if doesn't meet the criteria to be considered a frame challenge. If the police / agents are there openly then yes, local law enforcement can tell them no guns as per o.m.'s answer (which I upvoted). The use of the terminology "agent" suggests to me that they may be there undercover, however, and not declaring their weapons or purpose. As for saboteur motivation - that's what I was thinking. May 12 at 8:58
• No apologies needed. I meant it's a good answer and simply isn't a frame challenge. Your method can be ysed for a blanked gun prevention, assuming only the law carries arms and goes through the saboteur. I'm just suggesting improvements to consider for your answer. The last bullet point also states they are "common police officers", which doesn't rule out undercover but would most likely in all scenarios have some aid/interaction from the residing law enforcement. May 12 at 11:07
• And would the average officer even realize what the problem was if the firing pin was slightly too short but otherwise looked normal? Yes, there isn't an adequate dimple in the "fired" cartridge that would give it away to a gunsmith, but I can easily picture the average officer not realizing it. May 13 at 14:59
• This tactic reminds me of the Irish folk song Whiskey in the Jar. Steal the sword, mess with the ammunition and the target is ready to be taken in.
– Mast
May 14 at 9:01

I've got to say that Hippeus_Lancer's comment is the simplest:. There is a local law that prohibits guns, either in general or at least in routine use by the law enforcement personnel.

Your agents don't know this, they come into town and arrest someone, taking him to the local sheriff to detain him. The suspect complains that he was arrested at gunpoint. The sheriff lets him go and then bawls out the agents, because he knows the arrestee's lawyer will have a field-day if he tries to prosecute.

In a very real sense, the agents' guns "don't work." If they pull them out, the arrest is invalid and the perp walks. If you need to circumvent the "gun's don't work" scenario, you could have it so that they can be used if a warrant is obtained in advance. The process for getting one can be as simple or Byzantine as you need it to be.

Your agents do not bring guns.

It is not universal that all law enforcement officials are packing heat. In Britain many police do not have guns. In China many police do not have guns. The police are armed with batons and other weapons, but not guns.

In the US it is more unusual for police to not carry a gun, but not as unusual as a town in the 1980s US where no-one has a gun. I conclude there are strict gun control laws in that town. If it is the US maybe it is an alternate universe.

Your agent could, by virtue of his or her authority, bring a gun to a town with no guns. I can think of two reasons not to do it.

1: Agent is trying to blend in. People whose business it is to know will notice agent has a gun and remember that they do not. Proclaiming yourself as the superior outsider is not a great way to get cooperation from the locals. It is a great way to get avoided by people who know things you want to learn, but who are afraid of getting shot.

2: Agent does not need a gun to do harm. If the agent knows no-one has a gun, that is perfect. The agent is skilled in hand to hand combat but sometimes worries about getting shot by some twerp. No guns makes your agent the toughest person in town. That is not obvious until it is.

• +1. I more-or-less lived in a small (5k people) in Tuscany in the 80s, and maybe the two policemen had a gun, but locked away normally. Not carried in normal, main traffic control, duty for sure... May 15 at 8:28

I can think of no reason within the realm of 1980s science. Just consider, if there had been such a thing, don't you think the military and police would have employed it? Things get even more complex if you assume that it affects only this little town ...

• A (natural or genetically engineered) anti-material bacteria. The linked example is something which goes after oil, others might go after lubricants in guns.
• A coastal town with salt water spray in the air. Unprotected metal corrodes quickly.

In both cases, countermeasures would be possible if the agents knew in advance. I get the feeling that you are looking for plot-shattering magic in order to solve a plot hole.

Two thoughts violating your last bullet point:

• Through some accident of history, the town is actually an enclave completely surrounded by another sovereign nation. There are treaties to allow the easy transit of people (including government employees on official business) and most goods, but guns would need a special permit.
• Not an enclave, but the only practical way to get there is by air or by freighter, and the airline does not allow the transport of firearms or explosives (even for government agents).
• Brown's Point, Washington is exactly that. It's an American town on a peninsula, reachable on land only through Canada (though it's easily accessible by boat, that's slow, and it's too small to have an airport of its own). Doesn't keep residents from owning guns, but it complicates things for agents coming from elsewhere... May 12 at 12:43
• Until 2015, Dahala Khagrabari was (deep breath) an Indian enclave within a Bangladeshi enclave within an Indian enclave within Bangladesh. It is plausible that treaties and international relations could have at times made movement of people and goods... complicated. May 12 at 13:12
• @ZeissIkon, I'm more familiar with the situation in Europe. Some decades ago, armed customs agents were allowed to cross a border in hot pursuit, but not as a shortcut to get home after work. So when they had a roving checkpoint between the last highway exit and the border, they had to close the highway to back out again.
– o.m.
May 12 at 17:42
• BTW, In the USA, at least, airlines cannot bar Federal agents from carrying concealed firearms -- FBI agents and Federal Air Marshals routinely fly armed, and anyone with a Federal carry permit can do so. Not helpful if the FBI wants to visit Brown's Point, however; they still need to at least have the cooperation of the RCMP to get their weapons there if they don't come by boat or helicopter (and the latter is expensive enough they need a good reason for it). May 12 at 17:58
• So far as I'm aware, more liberal than today (may have included any police officer). The first real skyjacking only took place in the early 1970s, and armed air marshals were still a pretty new thing in 1980. There were no metal detectors at airports, though it was illegal to bring actual explosives. Small towns, however, often don't have a local airport -- where I grew up, the nearest with jet service (as opposed 18 passenger turboprop to the local) was 45 minutes away; nearest "international" close to two hours (90+ miles). May 12 at 18:10

They ran out of ammo

Simple enough. It's a Gun-free town. Nobody carries them, they disapprove of them on principle, and by and large things are good.

Then the agents showed up, got into a brief fire-fight with a pack of wolves and ran out of ammunition. Their guns are now entirely useless. There's no gunshop, no ammunition store. Even the police station doesn't keep ammunition, at least not in the calibres they need for their pistols.

Our intrepid agents must rely on their wits and whatever they can scrounge up from here on out.

Science Not Really

Guns are simple machines. Springs, hammers and triggers. There is nothing electrical in them so you can't really affect them in a way that won't destroy something else.

Bullets are not that complicated either and the gun powder and primer is usually airtight inside a bullet. The bullets are brass and lead so it would be hard to affect them without affecting everything else.

What you're left with if you want to stop guns in a fixed area is magic. Outside drug runners gunned down the local priest in cold blood and with his dying breath he cursed guns and the death they bring. From that day guns simply don't work inside the town. The town is remote and hardly anyone fires a gun inside the town itself so basically unknown to anyone but a local.

Only other option is super science so something like it's not really 1980 and everyone is trapped in something like the Matrix and a programming bug stops guns from working in the town. Another option is nanites who target and disable guns. Finally a mind control system that prevents people from triggering weapons. As much as they want to, they can't pull the trigger.

Undetectable gas leaks make firearms an explosive risk

This town does not take the usual step of adding an odour to natural gas to make it easily detectable. A majority of the town uses natural gas for heating but the whole town is run down to the point that gas leaks are common.

The people there will have adapted to minimize the risk; emphasizing big windows for natural light and ventilation, cooking outdoors.

A gunshot in an enclosed space is an unacceptable risk in any house when you can't detect a leak by smell. Your protagonists know this ahead of time and do not bring guns.

Maybe someone has deliberately engineered this situation through sabotage(?)

• It would also eliminate Automobiles, most electric motors, and all smokers. If a gunshot can set the gas off, then a good electrical spark can, too. Or a lighter. May 12 at 11:01
• Exactly, except for the automobiles. We're talking about indoors only. It's coming from gas leaks in the home. There wouldn't be enough to have it be hazardous outdoors. May 12 at 11:03
• Gas leaks at well below ignitable levels will result in deaths of humans and pets from pulmonary edema. This is the famous "canary in the coal mine" effect -- birds being more susceptible to this than mammals. May 12 at 12:39
• Yes but the scenario isn't that many houses have gas leaks at any time, but that the risk of a gas leak is deemed high enough for the agents to leave their guns at home. In the midst of a mission, an agent won't have the time to check the environs for secondary signs of gas leakage like sickly people or small dead animals. May 12 at 12:45
• But undetectable leaks leading to deaths is exactly why natural gas and propane are always adulterated with odorants. This originally came to light with coal gas (aka "city gas"), in which the carbon monoxide caused death pretty quickly. May 12 at 12:50

# Cold climate

Temperatures a little below 0F/-18C can cause a gun's firing pin to become sluggish, which will cause misfires. Just google for gun "firing pin" cold. In humid conditions this becomes even more troublesome.

There are plenty of towns in Alaska where you get such inclement weather for many months per year. Utqiagvik, for example:

The high temperature is above freezing on an average of only 120 days per year, and there are 106 days with a maximum at or below 0 °F (−18 °C). Freezing temperatures and snowfall can occur during any month of the year.

You can degrease guns and work around the problems of cold, but it may be that your agents did not have the time or resources to have done that properly.

# Sabotage at checkpoint

Also notice that Utqiagvik cannot be reached by roads; You need to take a boat or an airplane to get there, which provides for a point where the agents could be checked for guns. In such places, whomever is checking the guns may secretly damage them on purpose.

Other cities which are isolated and hard to get to might have a similar checkpoint issue.

# Humidity

Moisture inside guns can mess up the mechanisms for semi-automatic pistols - at worst they become unable to eject casings, thus jamming the weapon. If the town is constantly foggy guns will require constant maintenance for which the agents might not have the resources.

Notice that the solutions above are not 100% effective (climate is a chance thing, and sabotage may be reverted if the agents find out), but they are troublesome enough to lead gunslingers into a disadvantageous situation.

• To build on the idea of cold, add an aerosol agent that causes tool/hardened steel to become more brittle. A bit of that, a good freeze, some literary license, and you've got shattering firing pins. May 14 at 8:58

Frame Challenge: Let them keep their guns

If the agents must "work out what is going on" in the small town, that sounds like an investigation of a crime, mystery, or phenomenon. Guns only give an advantage in physical conflict, and even that is surprisingly limited. Unless you plan on there being a lot of Bourne-style Hollywood action, guns don't help your agents solve a mystery. If there is a climax involving physical danger that a gun would make short work of, include a plot reason the gun was inaccessible. There are also plenty of real-world factors that reduce their effectiveness, such as:

• Poor visibility
• Indoor close quarters
• Limited ammunition
• Risk of harming bystanders

That said, please research the capabilities and limitations of firearms. YouTube "Hollywood Gun Myths," or better, check out literal training courses.

• Fox Mulder barely fired his gun in 7 years, and there was no magical anti-gun effect in place. Guy just couldn't keep a gun in his hands even if he was glued to it.
– Tom
May 14 at 5:16

S.M. Stirling has a wonderful series of books called the Emberverse which portrays (among a variety of other physical law changes) the sever reduction in the combustion speed of gun powder. This causes bullets to fall out of gun barrels rather than flying out at killing speed. A number of different explanations for the changes are offered at different points in the series, but my favorite was one mentioned in passing during the first book.

To paraphrase...

How do we know that physical laws are constant across time? Isn't it possible that some universal constants (like the burning rate of gun powder) shift dramatically from time to time. If that shift only occurred rarely based on human perceived time, we wouldn't know about it. Perhaps late in the eighth century, a couple decades before gun powder was invented, the physical laws shifted to the state we are familiar with, and as a result, gun powder has behaved in its predictable useful way for only the last 1300 years. It might be completely normal for our universe to change things up every once in a while and we don't know anything about that because of the comparatively short time that we have had the technology to perceive it.

Addendum : It might be interesting to tweak the gun powder combustion rate in the opposite direction. Instead of slowing it, speed it up and lower the ignition point to below ambient temperature. Perhaps the reason that nobody has functional guns is that all of the ammo, including what was loaded in the guns all went off simultaneously in the first millisecond of the change. The guns which were luck enough to be unloaded at that moment would still be functional, but there would be no remaining ammo to put in them.

• This is an interesting approach, but confining it to a small town in the 1980s does smack more of "magic" than anything else. May 12 at 18:09
• Aside from the ‘magic’ aspect, it’s worth noting that the Emberverse approach of slowing down the combustion of gunpowder actually does not prevent firearms from being possible, it just makes rapid fire impractical and requires a redesign of the ammo (you would need a carefully calibrated rupture disc in the cartridge between the projectile and the propellant). It would work to suppress real world firearms, but only if it’s unexpected. May 13 at 11:42
• As I recall in Ember, the protagonist discovered a jewler's rouge that acted as gunpowder does in our universe, when he threw a rag into the fireplace and saw how it flared. May 14 at 16:21
• A small clarification here. The Chronicles of Amber was by Roger Zelazney and is about multiple dimensions. The EmberVerse series is by S.M. Stirling and is a post-apocalyptic set in a world where electrical circuitry, internal combustion and gunpowder have all suddenly stopped working. Corwin of Amber does find a compoound which serves as gunpowder in the furthest planes of the Amber multi-verse, and that is an interesting coincidence given the subject of this question, but it is not what I was referring to. My answer here is based on the writings of S.M. Stirling. May 17 at 22:56
• @JDługosz The one you are remembering is the Chronicles of Amber, specifically the second book, which goes into great detail about Prince Corwin's project to provide Amber, the one true city, riflemen, called "The Guns of Avalon." We should read it again! May 21 at 18:44

### Other than a sci fi anti gun ray, you should look at weather.

• A combination of dew and sub zero temperatures has been known to freeze firing pins in guns. They can also freeze fireing pins from simply a temperature transition due to condensation(Eg)
• Humity or condensation can spoil the powder charge. Moisture stops gunpowder from going boom, and low grade bullets letting the moisture seek in would fail in high humidity.
• Alternatively if it's a hot day touching metal is a very bad idea. Ive burnt myself by touching tools on a 45+ degree (C) day. If I touched a gun that wasnt kept in the fridge I'd burn my fingers.
• There's constant dust everywhere. If you draw a gun out of its protective case within a few minutes there's so enough dust in it that it needs to be stripped apart and cleaned before it can fire again.

### Or local manufacturing laws for bullets.

For example the banning of lead in consumer products forcing bullets to be made of something else, eg copper. The less lead seeping into the environment the better, and different materials for the bullets mess with the Obturation of the bullet as it travels the barrel. The linked wikipedia page shows that switching from lead bullets to copper bullets increases barrel pressure from 49MPa to 392MPa.

A gun not made for these pressures would be prone to misfire and catastrophic breach of its barrel when fired.

• +1 for the dust. Most gov't-issue firearms are designed to be able to hand being covered in dust, and still fire, but it's definitely likely/possible that in constant dust-storms some would jam up after a few rounds. Outside of a frame challenge like "local laws prohibit firearms" or magic, I think this the best answer OP's gotten. If OP likes the temperature route, note this will only apply if the firearms aren't being carried close to the characters' bodies. May 13 at 22:19
• I'd also vote for the gunpowder - though, note that humidity is the sort of thing that can foul bullets on the scale of months or years. But you could easily have one of the characters drop the ammo supply in a pond, fish it out and not dry it off right away, without telling the rest of the group. May 13 at 22:21
• You have misunderstood the linked WikiPedia article. The listed pressures are those needed to force a bullet completely into the rifling. If the pressure is lower gas escapes forward, and pressure drops even further. So switching material from lead will not increase pressure. Also, the values only apply to pure bullets. Real bullets tend to be jacketed. May 14 at 12:24

The Trigger by Arthur C Clarke and Michael McDowell is all about a device that detonates explosives remotely. This could be used to disarm agents approaching (and probably injure unwary ones).

I haven't read the book for years, but seem to recall the device is a beam that excites a resonance in nitrogen-based explosives. Wikipedia says the discovery in the novel was accidental and thus poorly understood; a blocking variant is developed later.

It's worth a read for inspiration on the implications, as well as for the central idea.

• The question asks for 1980s technology.
– Mark
May 12 at 21:46
• Piezoelectric transducers were around in the 1800's, the benchmark work being in the 1917 design of 50KHz underwater submarine detection. 1980's had easily the tech to accomplish this particular method (if somewhat vague in it's design specs). @Mark May 12 at 23:10
• @ARogueAnt., bond resonance frequencies are typically in the high gigahertz to terahertz range. You're not going to get that out of a piezoelectric transducer, and even if you could, I'm not aware of anyone using it to remotely detonate explosives.
– Mark
May 13 at 0:55
• That's a fair comment, but it's unclear what frequency and power might be required. I always remember the injunction against never dropping a loaded gun - they spontaneously fire. Perhaps we're talking about a frequency and power that might homogenize flesh at the same time, not sure really, or perhaps a resonant frequency of the gun body, or shell-casings. I certainly haven't tested this, and the tag's not hard science. Basically I'm not voting to delete as low-quality no matter what qualms I might have, because the idea might just have (a slim chance of having) merit. @Mark May 13 at 1:13
• @ARogueAnt., a dropped gun spontaneously fires when the impact with the ground causes the hammer to rise away from the firing pin and then drop back down, setting off the gun in more or less the normal fashion. Nothing to do with resonances, molecular or otherwise.
– Mark
May 13 at 1:19

The local supply of bullets has faulty primers. The officers went to the local range for practice/qualification and expended their working ammunition, then refilled from a new batch of local supply that no one else has used. Quite a shocking surprise when they pull their service arms in a situation and just hear a loud >click<.

• "The local supply of bullets has faulty primers." That's not how supply chain works; if there's a bad batch of primers, you contact the manufacturer, send back the bad ones, and get a new supply. May 13 at 7:34
• You have to discover that they are bad. Until you open a box, load them, and fire them, you do not know they are bad. Also, I don't believe it is standard practice to test fire a few before accepting delivery. May 13 at 16:25
• Another variant: for this mission the agents were supplied defective ammo by their agency and they don't realize it until they attempt to shoot their weapons inside the town. May 13 at 16:31
• Your answer completely ignores "there are no guns in the town and to prevent the agents from having an overwhelming advantage against the local people, I want to create a condition, mechanism or phenomenon that could stop guns from working" and "Preventing guns from working in the entire town would be perfect, but if this is not possible, preventing them from working just in closed spaces would be fine too." May 13 at 17:13

## Whoopi Goldbergs ... lots of Whoopi Goldbergs

There was a movie from the 1980s, I think it was Jumpin' Jack Flash, where literally every time somebody points a gun at Whoopi Goldberg she starts screaming in terror. It's the sort of common sense that makes for an uncommonly good movie. If the agents know that the sight of a gun will provoke a loud, ongoing reaction for cultural reasons, they could be severely inhibited.

## Star Wars prototype

The Strategic Defense Initiative sought to develop weapons that could incapacitate incoming nuclear weapons. First, they built prototypes with practical applications, and this town is the site of one of these systems.

Defying every bedrock American principle of freedom and privacy, secret agents have studded the town's skyline with sinister surveillance devices, which they call Cell Towers. These continually use multiple radio frequencies to scan for and track any radio-reflective devices. (Off topic: It is also rumored that there are microphones scattered all over town that the towers continually listen in on, but this seems far fetched - how could you convince Americans to carry around bugs? This isn't the Soviet Union!)

A bank of dozens of powerful IBM AT computers processes the signals, triangulates, and identifies each device according to whether it is a potential weapon. When a weapon or even a round of ammunition is detected and identified, powerful directional antenna arrays building on technology from the HAARP Program are able to broadcast highly directional signals that focus radio frequency energy on it like a microwave oven. Much of the energy is reflected, but the guns spark, heat, and possibly fire themselves under the onslaught.

Second Amendment advocates are substantially less than thrilled with the experiment, but as conservatives understand the importance of developing new defenses against Soviet assault. It is the price they pay for freedom...

Drug induced hypnosis

People entering the town are fed or exposed to a drug rendering them suggestible to hypnosis. They are then fed subliminal messages over the local radio/TV and other mediums 'suggesting' they forget how to use firearms.

They still know they exist but whenever they see one they can't remember exactly what they are used for. In fact perhaps they develop an aversion to them - they feel 'unclean', objects that are best left alone, untouched. Indeed picking one up induces a sense nausea or some other aversion to handling it.

## Mold

A unique mold is native to the local ecosystem and can only be found in that area. The mold seems to have an affinity for the chemicals in gunpowder, so it grows readily on firearms, magazines, and bullets. In its early stages it is hard to spot, and is generally only noticed when one is looking for it. Its organic chemistry reacts with the styphnates and other primers found on common bullets, turning them into duds. Nobody can keep ammunition for more than a few days without it becoming useless.

• The shell casing in most manufactured rounds is effectively hermetically sealed to the waste of the bullet. Your mold would have to eat through brass or lead to get at the powder charge. May 13 at 8:43
• Hypothetically, there could be a mold, bacteria, or yeast small enough and corrosive enough to permeate brass, copper alloys, and/or nickel. And ammo is far from "hermetically sealed." Military ammo has sealant at the primer pocket and around the bullet, and yet are still susceptible to exposure to moisture, oils, ammonia, and I'm sure a plethora of other compounds. May 14 at 8:54
• @GDeMasters But then everything metal would be dissolved, and steel in particular (which is far more vulnerable to corrosion). You can rule out metal beams, screws and nails, cars, cutlery, anything concrete apart from flooring/paths (because no rebar). Also all electronics. May 17 at 8:49
• @Graham Not all solvents dissolve all metals. Aqueous ammonia at room temperature will corrode brass, copper, and nickle, but not mild steel. The hypothetical microbe could produce ammonia as a by product. Microbes can only grow where there is food and only within a range of conditions, say relatively dry and cooler than 35­­°C. With these parameters, the microbe in question would have a fairly specific and limited environment in which to thrive. When commenting on Q&A tagged "science-based", avoid broad blanket statements and use facts to support your statement, not limited impressions. May 23 at 11:54

I'm no physicist, so I couldn't say anything about side effects on people or the kind of numbers to pull off this idea, but any material moving through a magnetic field generates current, and that current generates heat and diamagnetic resistance to the motion. If the town had some kind of magnetic anomaly, it could cause conductive bullets to veer wildly from their intended target and possibly soften enough in midair to splatter against hard surfaces.

# Gunpowder is neutralized by a naturally-occurring physical anomaly

Near this town there is some kind of physical field that has strange effects. The locals know about it, and have contrived some pretext to maneuver possibly-armed visitors through the field as they approach the town. Maybe the only road to town goes right through it, or maybe the pedestrian areas converge on a park built around the phenomenon.

The field is imperceptible and otherwise harmless, but certain of the chemical elements in gunpowder are transmuted into inert materials when they pass through it. Any gunpowder carried through this field is neutralized. It doesn't "magically" target gunpowder specifically, it's just that thoroughly mixed potassium nitrate, sulfur, and/or charcoal react this way within the field.

The field is some kind of dimensional wrinkle, but not in a useful way. It's not a stargate or a wormhole. What caused it? The Earth's history goes back a ways. Some time in the past ~4.5bn years, a shaft of high-energy particles pierced the solar wind and scarred this place. Maybe this effect will fade with time, maybe not. Just be glad you weren't here then -- you'd have lost more than your gunpowder. And be prepared to mix your own gunpowder from ingredients if you want to do any hunting in the area for the next stretch of geological time.

• I'm not downvoting your answer, but I'm tempted, because "agents" in the 1980's would definitely NOT be using black powder firearms as a matter of course. That is almost as far fetched as the magical reasons proposed for gun failure. Google, perhaps, DuPont and smokeless. May 14 at 8:54
• I googled "gunpowder ingredients" and got those.
– Tom
May 14 at 14:57
• Indeed. However, the gunpowder ingredients you discovered are for "black power," which would be the appropriate propellant for the 1880's, but not the 1980's. A little knowledge is dangerous; learn beyond the question, learn more than you need to know, then use the portion of that knowledge that is applicable. May 16 at 16:48
• This is just "because magic" though, because no such field exists or can exist within known physics. And adding magic is strongly plot-based, which tends to make it iffy for the worldbuilding forum. (Not because there's anything wrong with magic, but because your plot needs to have space for magic, and because the consequences of magic existing must impact on the plot.) May 17 at 8:44

If all mechanical devices are affected like clocks, radios, lights, engines, then we could jam the guns the pin won't work or the hammer acts as if rusted and won't move.

Otherwise we could use the region in a harmonical way to affect the molecules of the gun but this would affect again similar things basically a frequency or ground based radiance or tremor too small to detect by the human body and you can't bring in machines to feel it either because they've stop working.

In PA they have the singing rocks its said if you remove them they will stop singing in 24 hours. They basically sound like a hammer whacking an anvil when you strike them and visitors return them so its area based.

I would like to try and answer by asking some questions of the plot.

Where do super skilled retired master arms smiths go?...maybe your town?...maybe reports show it to be the safest in the event of a full nuclear exchange so they all decided to retire there and get their families moved as well?

What do they do to try and protect their families?...maybe set up an operation like the intelligence operations they used to be a part of that actively works to keep firearms from discharging utilizing all techniques from their former careers augmented by the fact that they are VERY experienced and unfettered by desire to adhere to laws or with desire to control anything else?...after all, what else is there to do a few weeks after you retire and continue to have clear mental abilities?

Maybe only targeting those they know through previous careers profiling people that have a higher than average chance of using a firearm in a deadly way?

Might not fit into a specific interpretation of the original posted need though.

This is possibly a duplicate of the previous answer suggesting sabotage...but with a proposed agent that is not totally nefarious.

The air is filled with a fire-retardant gas (specifially Trifluoromethyl iodide)

A fire retardant could prevent any flame or gunpowder from activating properly, significantly reducing or even outright stopping any attempts as using guns. This is especially the case with trifluoromethyl iodide, a fire retardant being experimented with by the US military to put out electrical fires in aircraft. It is less toxic than typical fire retardants, and has less ozone depletion issues.

Producing this and mixing it with breathable oxygen may provide the effect you're looking for, especially if the production of this is caused by plants or geysers overlooking the town. It is an irritant, but I can see easy ways to get around that for long term living, especially provided it's an important commodity in a semi-modern setting. Items like masks, eye protection, and coverings can fully quash any of the negative effects.

Any weapon fired in the area would already be saturated by this halomethane should it be in the air as particulates, and would be localized in a similar way to current fire retardants in forest fires.

• Read further down in your Wikipedia link and you'll discover a somewhat significant problem with it: in the presence of sunlight and water it can form hydrogen fluoride. Which of course would bond with atmospheric water to form hydrofluoric acid. So maybe okay if you don't want guns to work. Small issue with your lungs dissolving, of course... May 12 at 16:31
• @KeithMorrison That's only an issue at temperatures above 100C or when reacting with water, hence the "wear protective gear" disclaimer. Without both, the compound is stable. May 12 at 18:07
• This would only work against non-cartridge-loading weapons. Gun cartridges have an airtight seal between the bullet and the cartridge body, which will keep out your fire retardant.
– Mark
May 12 at 21:48
• Disregarding the fact that bullets use an internal oxidant, if there's enough oxygen mixed in to allow you to breathe then it will support combustion. The point of gasses like this is that they are heavy enough to displace the oxygen, starving a fire of oxidants. In a sealed room the oxygen is forced upwards, away from the probably location of the fire and probably into exhaust vents, removing the oxygen from the room. May 13 at 8:47
• Except that its fire-retardant effect is due to displacing oxygen (one leg of the so-called "fire tripod", the others being heat and fuel of course). It can only act as a fire retardant by suffocating both fire and people. And in any case this wouldn't work because gunpowder and other explosives contain their own oxidiser and do not rely on atmospheric oxygen. May 13 at 14:11

Could the town be some sort of experimental community, constructed on a lake bed or underwater? It would certainly have been possible with 1980's materials to construct a series of domes and tunnels under which the town was constructed. Perhaps created as an experimental counter-measure to the cold war at the time or a hangover from the space race?

Of course you could discharge a firearm in such a location but having high-speed projectiles flying about may damage the structure preventing the water flooding the town. You could either institute a firearms surrender on town entry policy or simply a gentlemen's agreement that firing a gun in the town would be a terrible idea, either works.

• The last bullet in the Q seems to implly they want the want the officers to draw their guns, fire, and "click", nothing happens. I suppose they only realize they can't risk damaging the dome when they're about to pull the trigger but that seems unlikely May 12 at 15:23