Half a croissant, on a plate, with a sign in front of it saying '50c'
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Spring Gun

A spring powered weapon.
  (+3, -1)
(+3, -1)
  [vote for,

This spring powered weapon resembles a typical firearm, except it fires highly compressed springs. The spring ammunition is best described as greatly scaled down truck air brake springs. These are about the size of a 12 guage shotgun shell. Because the springs have only limited shelf life they are purchased uncompressed, and the user requires a lever operated press to 'charge' them before firing, or in this case, springing.

The casings also include a small amount of lubricant that is released upon springing. Once sprung, the lubricant coats thhe rifled barrel of the Spring Gun, and the spring rotates, lubricated as if a screw inside the rifled grooves, stabilizing the round in flight. The Spring Gun can also be fire powered, featuring a gas torch flame heating the loaded breech to a high temperature, as this will allow for a more energetic decompression.

rcarty, Jun 03 2013

" regarding the barrel pressurization the lubricant can vaporize rapidly like popcorn oil, if the breech is torch fired " Maizechinegun
[normzone, Feb 12 2016]


       How much energy can you deliver this way? Let's assume that one ton (1000kgf or 10,000N) is the greatest force you can deliver to compress the spring, by means of the lever. Assume also that the spring is 20cm (0.2m) long, which is generous.   

       The energy stored in the compressed spring will be 1/2 x 0.2 x 10000=1000Joules. This is more than many pistols, and less than most rifles. So, not a completely silly idea.   

       On the other hand, it's going to need either one very very long lever, or a short lever that you pump a lot of times.
MaxwellBuchanan, Jun 03 2013

       It's not going to work, and here's why: the reason the bullet leaves the muzzle of a rifle going so lickety-damn- split is because it is propelled all the way there by a rapidly expanding cloud of combustion gasses. The propellant literally imparts constant force on the bullet from the moment of ignition all the way to the end of the barrel. The bullet does no work. A spring, on the other hand, does not enjoy this free ride. Not only must it produce sufficient energy to move itself, but once that initial surge of force is delivered, that's it. Friction with the lands will eat that up mighty quick, and there'll be no expanding gasses coming along to provide a boost.
Alterother, Jun 03 2013

       A crossbow, after hundreds of years of refinement, possibly represents the pinnacle of spring powered weapon capabilities. The low muzzle velocity (the biggest problem with the idea) in a crossbow is compensated by the shape and weight of the projectile.
xaviergisz, Jun 03 2013

       "Its not going to work" well for one thing the spring wouldint spin inside the grooves, that's were it screws up. But regarding the barrel pressurization the lubricant can vaporize rapidly like popcorn oil, if the breech is torch fired.
rcarty, Jun 04 2013

       If the spring were smaller in diameter than the bore of the barrel then rifling would still be applicable. If the spring extended past the end of the barrel then it should be able to be made to mimic the compression of expanding gasses.   

       Recoiling the spring for a second shot will be problematic.   

       //It's not going to work, and here's why:// It's not going to work _well_, but it will work, and here's why.   

       Given the (admittedly cumbersomly large) stiff spring, the total energy released is roughly similar to that of a pistol (same otm, at least).   

       For the pistol, energy is wasted in recoil, in frictional losses between the bullet and the barrel, in the expansion of gases beyond the muzzle, and in heat. The rest winds up as k.e. in the bullet.   

       For the spring gun, energy is wasted in recoil, in frictional losses between the spring and the barrel, and that's about it.   

       To a crude approximation, most of the energy winds up in the projectile in either case, if the gun and projectile are reasonably designed.   

       Where the spring gun loses out, though, is in the aerodynamics of the spring, and in the mass of the spring (greater mass equates to smaller velocity for a give k.e., so the spring won't travel as far or fly as straight).   

       You could get around these limitations by just using the spring to kick a regular bullet out the end of the muzzle - i.e. use the spring to replace the charge rather than the bullet. This would still be cumbersome, but with sensible design would give you a weapon that fired a pistol-style bullet at pistol-like speeds.
MaxwellBuchanan, Jun 04 2013

       To design a spring round for a conventional shotgun would be quite simple. First acqure a spring of right length, diameter and stiffness. Then compress in a press, after placing two notched caps on both ends of the spring. Then insert a lock pin that once turned cannot pass through the endcap notches. One end of the pin would have to be beveled so when the firing pin strikes it turns the pin to release the spring.
rcarty, Jun 04 2013

       // You could get around these limitations by just using the spring to kick a regular bullet out the end of the muzzle - i.e. use the spring to replace the charge rather than the bullet //   

       This has been tried in several modern weapons, most notably the PIAT, a WWII British anti-tank weapon known for its difficulty in loading and cocking, short range and abysmal accuracy, frequency of misfire, and the general hazard imposed on its operator and those standing nearby.
Alterother, Jun 04 2013

       Yeah, but this posting is the first BS gun.
MaxwellBuchanan, Jun 04 2013

       Not to mention my popcorn-powered steam rifle that used cubes of butter for projectiles.
normzone, Jun 04 2013

       Only because I have thusfar restrained myself from posting firearm-related ideas...
Alterother, Jun 04 2013

       Challenge accepted. Do you want a practical idea or a humorous one?
Alterother, Jun 04 2013

       Hardly, but I'm only going to do one gun idea, and I like to play to my audience.
Alterother, Jun 04 2013

       I thought we were in the Halfbakery.
Alterother, Jun 04 2013

       My ignorance of modern country music thwarts your earworm attack. Point: [The Alterother].
Alterother, Jun 04 2013

       Since it requires a special mechanism anyways, why not simply make it a smooth-bore ? Aerodynamically you can probably get some spinning out of a spring-shaped projectile.   

       Unlike a regular bullet, the spinning will count towards impact force as it corkscrews its way into the target.
FlyingToaster, Jun 04 2013

       The spring doesn't have to be the main projectile, the locking pin in my previous anno can be the bullet.   

       Regarding halfbaked weapons, weapons are one of the most halfbaked things because it's something that should stay at the conceptual stage.
rcarty, Jun 04 2013

       Now that's country music!   

       Stay tuned...
Alterother, Jun 04 2013

       If you make the spring big enough...the gun itself could become the projectile.
Ling, Jun 05 2013

       <quietly enters room and whispers to 21Q> Psst - Alabama did that Texas song, not Brooks and Dunn. <sneaks back out the way he came in>   

       Point: [Canuck]
Canuck, Jun 05 2013

       I wasn't aware listening to country music automatically makes one a redneck. Besides, I'm Canadian. How could I possibly have a red neck when we have eleven months of snow and one month of bad hockey ice?   

       Oh, I understand now - chafing from the scarf, eh!? : P
Canuck, Jun 06 2013

       Maybe you should get an iPad.
Alterother, Jun 06 2013

       This time next year, that'll be on reality tv.
not_morrison_rm, Jun 06 2013

       Instead of torch firing the breech the spring can be a resistor load for electric current.
rcarty, Jun 06 2013

       Patience, grasshopper. I have a lot on my plate right now, but I'll get to it.
Alterother, Jun 06 2013

       Don't compress the spring. Extend it. Have a coil spring attached at the muzzle, with an ID of say 20mm. On cocking the weapon, the free end of the spring is pulled back to the breech, whereupon it is secured by the sear, and a projectile is clipped onto the spring end. Pull the trigger and the spring retracts and launches the projectile. This puts the barrel into compresison, so it'll have to have sufficient diameter and stiffness to support the load, but beyond that I think this would work better.
Custardguts, Feb 12 2016

       I like Custardguts modification. The spring should actually be longer than the barrel of the gun by about 50%. After firing this excess spring will droop out the front, bobbing around. A small sign declaring "BANG" attached to the end of the spring would not decrease the workability of this idea.
bungston, Feb 12 2016


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