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Aquaticulture t1_j4isv6m wrote

The KRISS vector changes the angle of recoil to avoid muzzle climb and perceived recoil according to the Wikipedia.

You would still be propelled in the opposite direction.

Unless you were expelling mass with the same force in the exact opposite direction, firing a gun is going to impart force upon you and cause you to move.

Mass is not irrelevant in a vacuum btw (or in micro gravity which is what I think you meant to say).

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TyphusIsDaddy OP t1_j4itone wrote

Micro gravity is probably what I meant, Im definitely not a scientist. Whats the difference?

Also I thought mass would still be relevant, just couldnt work around how. Is it because the energies from the bullet are being transfered into the recoil dampners/springs, but theres nothing counteracting the weight of the bullet?

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OnlyAstronomyFans t1_j4j24el wrote

Not a physicist but the way I understand it you’re always subjected to some amount of gravity in space, but as you’re orbiting the planet/sun/galaxy/center of mass you’re constantly in freefall.

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flowersonthewall72 t1_j4ixjis wrote

Micro gravity and a vacuum are two different environments. We can create a vacuum on the surface of earth (full of gravity) or have the space station have micro gravity with no vacuum inside the station itself. The depths of space have both micro gravity and a vacuum.

Mass is certainly relevant in micro gravity. Kinetic energy (like a moving bullet) is bound to mass. More mass, more kinetic energy. So if you were to shoot a heavier bullet at the same speed as your vector, the bullet would have a higher energy. Then equal and opposite forces blah blah blah...

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404_Gordon_Not_Found t1_j4itnjy wrote

The recoil suppression system doesn't eliminate recoil (only tiny amount of energy lost as friction, etc), rather it spreads the recoil over a longer time and redirect the force downwards.

Therefore the gun would act as thrusters just like any other guns.

If you would like a more mathematical/physical way of thinking this, try the conservation of momentum. When a shooter is holding a gun in space no moving, there's no momentum. As the bullet is fired it gains momentum. Since the recoil suppression system is part of the gun, naturally the gun and the shooter would be imparted with an equal but opposite momentum.

Lastly, tell your friends that recoil suppression system is 'supression' not 'elimination', the shooter can very clearly feel the recoil.

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TyphusIsDaddy OP t1_j4iuzal wrote

Thank you for the detailed answer. Now the wonder is if you would feel the recoil of the gun, or if you and the gun would mover perfectly as one. Friend 1 thinks you would feel the gun as it imparts its forces on you, but wouldnt feel the acceleration backwards

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pmMeAllofIt t1_j4jj3b5 wrote

Shooting a gun with a typical hold would send you into a constant multi axis spin as well. Seeing as the forces are being applied off your center of mass. It's not like you would just fly backwards.

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404_Gordon_Not_Found t1_j4ivkwy wrote

You definitely would feel the backward acceleration of both the gun and you moving backward. This is exactly because you and the gun aren't one single rigid entity. If you have watched any slow-mo gun firing footage you will see the gun moves first after a bullet is fired, then the shooter's arm starts moving a short while after. The same thing would happen in space.

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OnlyAstronomyFans t1_j4j2j5d wrote

I own a vector 45 and believe me, it for sure has recoil, but it’s back and up instead of towards my gun hand.

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Nerull t1_j4iu04b wrote

Putting it in space makes it really easy.

Put the person in a black box. We don't care what happens in the box.

A bullet flies out of the box with momentum +p, the box must gain momentum -p. There is no way around this.

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FriedmanMkIII t1_j4j1tr9 wrote

Yea, but the resultant velocity of the box and bullet would depend on their respective masses.

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immortalis88 t1_j4iyl9q wrote

Whoever fires that gun is going backwards. Conservation of momentum. Equal and opposite reaction. It’s how propulsion works. Shit goes out one end and force is exerted in the opposite direction. Simple.

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DogeVegasSupreme t1_j4itofc wrote

What would happen if you just hung the gun by a string and pulled the trigger? I'd assume it would still go crazy.

I'd assume that crazy would impart to the shooter in space

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enutz777 t1_j4js3pr wrote

In order to get a true reduction recoil you would have to design a hollow tube gun such that the shell is projected backwards with the same momentum as the bullet traveling forward.

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crippledjosh t1_j4itpwx wrote

Firstly it's not the vacuum that's important it's the lack of gravity (or any other forces) acting on you. Therefore making any force that does act on you cause acceleration. Mass is in no way irrelevant, force=mass*acceleration and any force has an equal and opposite one. The force of the bullet moving out of the gun will be applied directly to the body firing the gun and accelerate that body by force/mass

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TyphusIsDaddy OP t1_j4iul65 wrote

So what im hearing is, using a recoil suppression system in space would actually CAUSE recoil, because the forces would be propelled downwards in an attempt to counteract recoil in earth gravity

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ShyElf t1_j4ixvn8 wrote

A lot of recoil suppession systems direct the exhaust gasses somewhat backwards, and would work to their normal effectiveness in space. This is most common with artillery. What the gun you mentioned does is kick the back of the gun up at high frequency (and pull it down slowly) in order to attempt to keep the barrel angle from changing while shooting. This would have almost no effect on the recoil push in space.

The cold is not a huge issue. Space is an insulator, so as long as you don't leave it in space for a long time without holding it, it should be fine. Overheating would be a bigger issue, but it would still be somewhat useable. Vacuum boiloff of lubricants and degredation of explosives would be an issue, but I would think it would still be useable.

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crippledjosh t1_j4ivgvi wrote

I'm not familiar with how recoil systems work, in total you've still only possibly got acceleration for the exact amount of the mass of the bullet * bullet acceleration/mass of the shooter and in the opposite direction of where the bullet went

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Soup89 t1_j4iwqg9 wrote

Momentum is always conserved. The force at which the bullet leaves the barrel is the same force that you would feel from the gun pushing back. The Kriss vector would just turn some of that backwards force into downwards force.

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OnlyAstronomyFans t1_j4j2o7u wrote

I own a vector 45 and believe me, it for sure has recoil, but it’s back and up instead of towards my gun hand. It’s a fine firearm, fairly ambidextrous, except for the charging handle, but it ain’t magic. Nothing 100% suppresses recoil, you should encourage your friend to take a physics class.

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Observer414 t1_j4jd0ig wrote

If you shoot a gun in space would it ever slow down

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space-ModTeam t1_j4k0z73 wrote

Hello u/TyphusIsDaddy, your submission "Maybe you all can settle this debate. What happens when you fire (Wait for it) a gun with a recoil suppression system, such as the KRISS Vector, in vacuum?" has been removed from r/space because:

  • Such questions should be asked in the "All space questions" thread stickied at the top of the sub.

Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please message the r/space moderators. Thank you.

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