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scorpiooooooh
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The debate is about the propagation of buckshot in the vacuum of space, which is similar to a question someone posted here in Astrophysics back in 2006. The discussion is taking place in a gamer forum where the participants are players of a game titled Halo: Reach. What started out as a simple random rant posted by someone in the forum has turned into a debate hotly contested by a bunch of folks whom clearly lack a comprehensive education in physics (including myself, guilty as charged).
The original question (rant) was this:
"why don't shotguns have infinite (correction: very long) range in space/anti-gravity rooms?
vacuum / zero g = no friction = nothing to slow down bullets = the velocity won't drop for very long periods of time"
On one side of the argument, some believe the buckshot should propagate in exactly the same manner as it would in Earth's atmosphere at sea level.
On the other side of the argument, some believe that the vacuum of space drastically changes the dynamics and that the buckshot will maintain a substantially tighter grouping over great distance.
For those who are not familiar with shotguns, a shotgun shell consists of (a) a plastic or paper shell casing, (b) the brass at the base of the shell, (c) a primer that is inserted in the center of the brass base, (d) the powder charge, (e) the wad which consists of three parts - the powder wad, the cushion, and the shot cup. (f) Lastly, in this case, 0000 (quad-ought) buckshot buffered with a granular filler of saw dust or plastic.
The shot cup has four slits along the length. The purpose of the slits is to cause the shot cup to expand (bloom) the moment it exits the muzzle, essentially slamming on the brakes, forcing it to peel away from the buckshot.
The folks at Bungie provide elaborate descriptions of the weapons used in the game.
The specs of the shotgun and ammo are as follow.
M45 TS (Tactical Shotgun) - 8 Gage 3" Magnum - 24" barrel - Mfg. Misriah Armory
Shotgun Shell - Hippo Mag (Magnum) - 8 Gage - Shot size, 0000 (quad-ought) - 15 balls of shot per shell - Shot size 9.5 mm (nominally) - Shot weight 2 oz. - Mfg. Soelkraft.
From what I have gathered reading archived posts here in physicsforum and other sites is this:
* Gunpowder will burn/explode in space (even under water as long as the powder remains dry) because an oxidizer is already present in it's chemical compound. The low pressure environment probably influences the dynamics of burn rate for the gun powder.
* The vacuum of space in near Earth, mid-Earth and far Earth orbital zones present negligible opposing forces (as compared to Earth's atmosphere at sea level) to everything that exits the muzzle of any firearm. Interplanetary and deep space present exponentially less matter per cm sq. Caveat - While gravity is always a factor, the scenario presented assumes what is commonly referred to a zero gravity.
* The propellant gasses should instantly dissipate omnidirectionally into the extreme low pressure environment of outer space the moment it exits the barrel. The difference in pressure between space and the propellant gasses is go great that the energy of the gasses becomes irrelevant outside of the barrel. (this is relevant as some folks postulate that the exiting gasses would influence the spread pattern from behind because the gasses continue to push the load after it has exited the muzzle).
* Without an atmosphere, there will not be sufficient drag to cause the shot cup to bloom. Therefore, the peeling away of shot cup may not occur at all or it will occur at a substantially greater distance from the muzzle. Conventional ballistics cease to be relevant outside Earth's atmosphere.
You have probably reckoned by now that I support the side of the debate that postulates the shot will remain in a tight cluster and loose little energy over greater distance. After reading the poster's question, my first thought was "what a stupid question". Having given it some thought, it turns out to be not as stupid or easy to figure out. Is there any real world application to finding definitive answers about shotguns in space? Maybe not in gunsmithing anytime soon, but the science may be applied to other real world situations. If nothing else, the debate is a good learning experience that promotes critical thinking and science. In my book, that alone is pretty worthwhile.
Your time and consideration in helping resolve the debate will be very much appreciated.
Scorpio
The original question (rant) was this:
"why don't shotguns have infinite (correction: very long) range in space/anti-gravity rooms?
vacuum / zero g = no friction = nothing to slow down bullets = the velocity won't drop for very long periods of time"
On one side of the argument, some believe the buckshot should propagate in exactly the same manner as it would in Earth's atmosphere at sea level.
On the other side of the argument, some believe that the vacuum of space drastically changes the dynamics and that the buckshot will maintain a substantially tighter grouping over great distance.
For those who are not familiar with shotguns, a shotgun shell consists of (a) a plastic or paper shell casing, (b) the brass at the base of the shell, (c) a primer that is inserted in the center of the brass base, (d) the powder charge, (e) the wad which consists of three parts - the powder wad, the cushion, and the shot cup. (f) Lastly, in this case, 0000 (quad-ought) buckshot buffered with a granular filler of saw dust or plastic.
The shot cup has four slits along the length. The purpose of the slits is to cause the shot cup to expand (bloom) the moment it exits the muzzle, essentially slamming on the brakes, forcing it to peel away from the buckshot.
The folks at Bungie provide elaborate descriptions of the weapons used in the game.
The specs of the shotgun and ammo are as follow.
M45 TS (Tactical Shotgun) - 8 Gage 3" Magnum - 24" barrel - Mfg. Misriah Armory
Shotgun Shell - Hippo Mag (Magnum) - 8 Gage - Shot size, 0000 (quad-ought) - 15 balls of shot per shell - Shot size 9.5 mm (nominally) - Shot weight 2 oz. - Mfg. Soelkraft.
From what I have gathered reading archived posts here in physicsforum and other sites is this:
* Gunpowder will burn/explode in space (even under water as long as the powder remains dry) because an oxidizer is already present in it's chemical compound. The low pressure environment probably influences the dynamics of burn rate for the gun powder.
* The vacuum of space in near Earth, mid-Earth and far Earth orbital zones present negligible opposing forces (as compared to Earth's atmosphere at sea level) to everything that exits the muzzle of any firearm. Interplanetary and deep space present exponentially less matter per cm sq. Caveat - While gravity is always a factor, the scenario presented assumes what is commonly referred to a zero gravity.
* The propellant gasses should instantly dissipate omnidirectionally into the extreme low pressure environment of outer space the moment it exits the barrel. The difference in pressure between space and the propellant gasses is go great that the energy of the gasses becomes irrelevant outside of the barrel. (this is relevant as some folks postulate that the exiting gasses would influence the spread pattern from behind because the gasses continue to push the load after it has exited the muzzle).
* Without an atmosphere, there will not be sufficient drag to cause the shot cup to bloom. Therefore, the peeling away of shot cup may not occur at all or it will occur at a substantially greater distance from the muzzle. Conventional ballistics cease to be relevant outside Earth's atmosphere.
You have probably reckoned by now that I support the side of the debate that postulates the shot will remain in a tight cluster and loose little energy over greater distance. After reading the poster's question, my first thought was "what a stupid question". Having given it some thought, it turns out to be not as stupid or easy to figure out. Is there any real world application to finding definitive answers about shotguns in space? Maybe not in gunsmithing anytime soon, but the science may be applied to other real world situations. If nothing else, the debate is a good learning experience that promotes critical thinking and science. In my book, that alone is pretty worthwhile.
Your time and consideration in helping resolve the debate will be very much appreciated.
Scorpio