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How hard would it be to make a dual-mode handgun or shotgun that, depending on how it's fired, shoots either lethal or rubber / electric slugs?

Not as in it's merely stocked with successive rounds, but that it actually has two separate clips and two separate firing methods that are distinct enough that someone who's under heavy adrenaline can shoot the correct one with absolute certainty and reflex action, somehow prevents being loaded the wrong way around, etc.
Val Schuman's profile photoKenneth Lakin's profile photoSimon Bridge's profile photoRyan Castellucci's profile photo
Or.... It could have no lethal ammunition at all. 
Haven't got a full answer, but I think a double trigger is required. Eg a trigger and a button for lethal bullets, and just a trigger for the rubber bullets.

OR a trigger with which when pressed standard pressure fires bullets, but when pressed even harder (depresses another 5 mm say), it then fires bullets.

Finally, I think there are already such weapons that can dire both tasers and rubber bullets, or both rubber bullets and live ammunition, or both live bullets and explosive grenades. Or am I confusing the first person shooter games with reality? :)
I think that there is seldom a case for deadly force. Effective less than lethal technologies exist that can completely render the target compliant. What +Line Bell said

Dammit! I wrote a good reply and I pressed cancel ;(

Ok, I think dual ammo weapons already exist. Eg taser plus rubber bullets. or live bullets and explosive grenades.

Re a new weapon, how about adapting the trigger such that standard pull fires rubber, extra harder depression fires live rounds. The extra depression maybe another 5mm stiff pull. The weapon will need two chambers.

Alternatively, rubber bullets standard trigger pull, live bullets requires the pressing of an additional button or lever on side of weapon. ?

EDIT: Oh now my original comment chooses to appear. Sorry +Sai
It shouldn't be very hard for a dual-barrel shotgun, which is a common hunting weapon. (Though, as a hunting weapon, it's not very likely to be even a remotely suitable for any purpose that mandates this design feature :))
Usually implemented as two guns welded together - as in an assault rifle with under-slung grenade-launcher. Mixing lethal and theoretically-nonlethal ammo looks like an accident waiting to happen - there are enough "I didn't know it was loaded" without "I forgot I'd left it on 'lethal'".
I can imagine a situation which would help with a weapon whose first shot is a taser dart and the next a bullet. No need to mess with the chambering and no arguments about due warning and so forth.

Similarly one could have the first x rounds as rubber bullets.

Do not see how being able to shift within the same weapon helps so much - but then, NZ does not routinely arm the police.
Or different modes of lethal ... it seems sensible to me since making a mistake between modes is less of a problem than when lethal and non-lethal get mixed.

The trick is not so much distinct enough that someone who's under heavy adrenaline can shoot the correct one with absolute certainty and reflex action but people not possessing the weapon being certain that those with the weapon won't make a mistake.
+Simon Bridge wouldn't it be better if the first shot was bullet, then stun the victim. So further shots are not necessary?

Because if you're going to fire a lethal (possibly lethal) then why bother with the stun/rubber before hand?

Objective being, the officer has decided they need more lethal shot, then if the perp is not dead, stun them and arrest them?

I guess there could be different options / scenarios too.
Also there may already exist good reasons or legislation why non-lethal and lethal combos don' exist! Note, I haven't done an exhaustive search.
+Satyr Icon Some people may be happier if lethal force is only used when other options have been attempted. I can't tell if you are being serious or not.

If the stun does not work then you have a clear case for more force being needed and right away. The other way and the officer's judgement is more open to question.

However - I've seen enough enthusiastic tasing to be unsure of giving officers the option of making the next shot lethal.
Well the reason I suggested bullet first then stun is that I don't see the reason for the combo of stun first, then bullet? Why even use a bullet (possibly lethal) when the perp is possibly stunned/immobilised?

However if stun/rubber didn't work, or if the officer decides that it wont be sufficient, s/he should go for bullet (hopefully to leg, arm, torso if necessary), then presuming it still wont kill, apply stun. So am suggesting using lethal bullet as a more effective measure /resort to slow down or immobilise a more serious threat. Not to kill. The follow-up stun to make sure, rather than a second bullet to kill.

But you are right, officers under real situations and after trigger happy training may not be able to think that way.

So yes, I'm serious, but maybe we're mis-communicating?
I hate guns. I'm in this thread for the mere engy tech aspect :)

Ok, I'm off to enjoy dinner.
V is me
Dude, people under heavy adrenalin apparently can't even reliably grab the right weapon given a choice; what makes you think we could possibly invent a dual-mode weapon that would be more foolproof than that?
Make the shooter perform a process that's quick, but requires higher level thought, in order to shoot lethal. Like... put four touch-screen keys on the side, and make the shooter press them in a specific order in order to select lethal. Have lethal mode turn automatically off after N minutes of inactivity and give a manual lethal-off switch.
I think, for the purposes of this question, one should assume that it is possible to flawless accomplish any conceivable firing interface. This is mostly an interesting problem from a UI perspective. The problem is that even if the shooter can be sure they won't accidentally shoot contrary to their intention, their intention is more of a problem - they'll intentionally shoot lethal rounds when they oughtn't.
+Ryan Castellucci why do you think that? Cops presently carry guns and tasers. It doesn't seem that they are using guns when they should be using the tasers...
What I'm trying to say is that I suspect that error-in-intent is more of a problem than error-in-action, but that's just my intuition on it.
I would feel very uncomfortable when combining lethal and less-lethal rounds in that Arsenal pistol that you linked to, Sai. The side-by-side trigger configuration that I think I see in the pictures wouldn't give me a lot of confidence that I was selecting the right ammo to fire.

Frankly, the consequences are far too high to be mixing ammo types in a single weapon. As the BART security demonstrates every couple of years, it's "hard enough" to determine which gun is the less lethal one. We should not get in the habit of making it that much easier for shooters to get confused about what level of force they're gonna project.
+Sai I don't think it can be in any practical way - you'd have to delay and force the user to think about it, which may well get the user killed.
I'm with Ryan - when we engineer these sorts of safeguards we do it by removing choice from the user (i.e. the outer door of the airlock cannot open unless the inner door is sealed or gas only flows to the pilot light if it is lit) ... but the design calls for increasing the users choices.

This is a good sign the wrong question is being asked. What is the problem that +Sai would expect to be solved by this kind of weapon?
What, that both reliably fail to kill and take out the perp? With no risk to bystanders?

That would be a good trick.
Like I said - a good trick.
Adding "unnecessarily" requires the device to be psychic too.
How is the device supposed to decide how much damage is needed to do that?

Usually, when someone is rendered helpless, the only sure way to know if the force used was the same as the force needed is in the autopsy.
They have the disadvantage the they can kill someone who has a weakness and have little effect on someone juiced up on some drug cocktail - well done.

Whatever you pick, it's going to let someone through and be too hard on someone else and there is no reliable way to tell, a priori, which is which.

eg. you need to be psychic.

So you relax the criteria - you want something at least as reliable as a sidearm or a shotgun but less likely to kill and less chance of bystanders being affected. This is a work in progress.

It's also why I asked the question: what is the problem +Sai is thinking of, that the kind of weapon he's proposing is thought to solve?

The only thing I can think of would be the situation where you grab your taser and realize you should have grabbed your firearm with no time to swap. (Usual answer is to run away - or hope your partner is on the ball.)

What force is appropriate is a judgement call.
What you end up with is the engineer and policy-makers deciding what options are available to the person in the field.

You takes your pick and takes your chances.
What? An argument does not have to be particular to a situation to have bearing on it. This is why we spend so much time and effort figuring out general laws of nature.
Yeah - right past each other.

So lets recap... you touted "effective" non-lethal weapons, I point out that, on general principles, that cannot happen. There are just too many variables.

You can try developing more effective non-lethal weapons, with more reliability. But you won't have reliable weapons ever.

I'm pretty sure you did not really intend to write in absolutes.

All this is besides the point - first specify the problem to be solved, then come up with the invention. In both cases considered the problem is under-specified.
Yep - you produced the same scenario I did.
The problem is where you need to quickly escalate.

This actually works well with successive fire - 1st shot the less-lethal option. In your exact scenario - someone pulls a knife, first trigger pull fires, say, the taser, and if that does not work you get the regular firearm.

No waiting for the decision.
Target out of range and you don't want to wait - pull twice in succession.

But you wanted the officer to have a choice on the fly - so what is the problem that being able to choose on the fly solves?

I'm surprised: you usually have a real-world example.
Oh BTW: the answer to the opening question is "not hard".
Its the deployment and training that is hard, and it is not clear that other solutions would not be more practical.

What we really need in this discussion is someone actually in law enforcement.
De-escalate is not an issue if the first shot is mandated low-lethal and escalation is as fast as you can pull the trigger ... which satisfies both requirements and simplified the UI.

Skillset is the same as current.

I don't need to propose a mechanism that can be reflex-trained because my position is that it cannot be done. You have set unrealistic specifications. If you believe otherwise, then come up with the mechanism.

Though you never said it was restricted to cops only, I was speaking to the example you used. However, you should realize that the idea that civilians have a legitimate reason to be armed is culture-specific. NZ, for example, has gun control instead. It is illegal for citizens to go about armed.

However, with regard to the US situation the same applies double since civilians are seldom well trained in the use of weapons. You don't want to rely on the users judgement ...

Bottom line: you have yet to explain why the user needs to be able to switch at will between modes of attack. You seem unable or unwilling to articulate this ... why is that?

Without this quite elementary bit of information any design will be unsatisfactory. The problem remains under-specified.

C'mon, you can do better than this!
Let's pretend we're in that fantasy land where arbitrary weapon UI can be implemented.

Consecutive load could be emulated - mode switch on the gun selects between 'always fire less-lethal', 'always fire bullets', and 'fire less-lethal if trigger hasn't been pulled in the last five seconds, otherwise fire bullets'. The weapon always switches to the last mode when holstered and after a 15 minute timeout. Add a very clear visual indicator as well, a large portion of the weapon changes color and there could be tactile feedback (how the grip feels) as well.

You could alternitivly have the default mode be "won't fire at all" and require some mode set action at draw time.
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