Hunting on the moon.

Yes. Yes they do. And in the instance of the image, considering the relatively low velocity of a bullet, it will go into a highly elliptical, ultimately terminal orbit.

well there you have out-physicsed me

Yep, plus in space they don't need silencers!

very good. tell me more...

If a gun was fired remotely in a low gravity environment, the recoil would send the firearm spinning wildly off in the opposite direction. That would be pretty cool to see now that I think about it. Hey! Points for posing a thought provoking question!

Combustion requires fuel oxygen and ignition, and ammo contains an oxidizer (which is also why it works underwater). As long as the ignition generates enough heat to bring the fuel to the combustion point, bang. Space guns might require a heating mechanism to keep the fuel warm enough, or a more intense ignition mechanism.

But yeah, pew pew, no sound, and missed shots will sail off until they establish a stable orbit or crash into something.

Nope no need for any heating the primer cap inside of the brass casing will do that for you it it were just a firing pin and a striker maybe but thanks to the primer cap the gunpowder will ignite no matter the circumstance and the recoil can de compensated by divert ING the gall out of the sides however this presents a unique challenge of even distribution of gas

I'm not sure that the primer or powder would ignite at -170°. Glock makes some models with ports on top of the barrel just behind the muzzle. (They work pretty well but the flash obscures the sites.)

When the firing pin hits the primer it creates a micro explosion igniting the gunpowder no matter the outside temperature

that's a good point about temperature. i hadn't thought of that. i'm not sure i agree about the recoil effect tho. the force of recoil shouldn't be affected by gravity, only by inertia, which should be the same under any gravity. so, remote firing in earth gravity should show the same force of recoil and action on the gun trajectory. what about impact on bullet speed? bullets on Earth slow down because of air resistance.

Heh, the recoil part is counter-intuitive but Newton's Third Law shows that there's the same amount of energy pushing forward on the bullet as there is pushing back on the gun. Some of the gases get redirected into mechanical energy, but the rest goes into hurling the firearm the opposite vector from the round fired. Both of them will maintain a velocity consistent with Newton's First Law, which in the vacuum of space means basically indefinitely.

exactly. so if you remotely fired a pistol hanging on a string in Idaho, you'd get the essentially same degree of recoil as in space. i'm saying no need for a low-gravity environment.

Hmmm...I'm not sure about the formulas because I spent most of math class doodling, but gravity would act on any kinetic force within its influence. If the gun was pointed down, gravity would act completely in opposition to the recoil. If the gun was pointed up, the pull of gravity would add to the force pushing it towards the earth. If the gun was pointed straight ahead then gravity would have an effect somewhere in between. In all cases I think the outcome would vary significantly from a gun fired in an extremely low gravity environment.

well i think of it like this: if i stand in my back yard and point a gun straight up, i feel gravity pulling on the gun, just as it does when i point it at the horizon. the force of gravity on the gun is the same in each case since gravity depends only on the masses involved (which are the same in each case). whenever i fire the gun, the force of recoil adds as a vector to the force of gravity. when pointing the gun straight up, the force of recoil towards the Earth might seem stronger because it adds linearly to the force of gravity, but neither force is actually greater than in the horizon shot. in the horizon shot, the vectors add orthogonally. and recoil depends only on the amount of gunpowder and the masses involved (which are the same in each case). or in other words, forces act on masses but not on forces. if the masses are the same in two scenarios, the recoil force should be the same.

Gravity is very minimally affecting the gun because it's a small and bot that heavy objects compared to you the force of recoil in space would be the same but there is nothing to affect the forces so the answer is yes and no as the bullet travels in gravity it would lose speed but foe about one second it would speed up after exiting the barrel of the gun the only reason for the slowing down is gravity so in space it would have a constant increase velocity as long as there is no other force interaction so the gun you have just fired in space would do the same and due to the rifling on the firearm it would spin so you would need to divert the blowback from the gas explosion in the barrel both backwards and in opposite rotation of the rifling

i think gravity can only slow the bullet until it reaches the height of its parabolic arc, then it would regain speed as it approached the moon or other massive object. i don't think it can increase in speed for any other reason since the force of the explosion ceases after leaving the barrel of the gun. now i hadn't thought of the rifling, but shouldn't it have the exact same effects as in a high-gravity environment?

No the rifling can and will cause torsion on the user's hands that's why during the 60s the Russians designed a shotgun that when tested was quite effective ot was called the tp-82

but why would it be any different in space?

the rifling impact, i mean

Due to no gravity the gas exiting the chamber through the bolt and barrel will exit in a spiral motion causing torsion

That makes sense. Gravity would affect inertia, not force.