I had the idea of a "void weapon", which would "generate cold" rather than heat on triggering. All the air from the chamber would be sucked out (thus "creating cold") and on firing, it would open the chamber: the difference of pressure would push the bullet out. However I'm not sure it would be powerful enough or even feasible.
I was wondering whether an endothermic weapon was possible. If so, how would it work ?
- Current technology
- Must be endothermic: it can produce energy, but when shooting, the total sum of produced and removed energy must be negative. Energy stored in the bullet, if any, doesn't count: else that wouldn't make sense I guess.
- The endothermic part of the gun is mandatory for it to work (don't stick an ice cube machine to an M16, or just put an icicle on a crossbow...).
- Endothermic part can be part of a cooling system, but if you can come up with something a little bit more original, it'll be better (though it's not forbidden)
- You can use the "void weapon" idea
- Can be used and moved by just one person. Maximum size and weight: rocket launcher (with a backback)
- Doesn't need to be reloadable or have more than one "shot" (was gonna say "bullet", but it can use something else, doesn't have to be a kinetic weapon).
- Can kill one person without bulletproof vest
- It's an experimental weapon: it doesn't have to be mass produced (almost infinite budget for R&D)
- Bonus point if the endothermic part is visible (frost on canon, cold steam pouring out, etc.)
EDIT: after comments, removed hard-science: we just need approximate concepts.