Unless I'm severely mistaken, this is incorrect. Muzzle energy and recoil energy have to be equal, it's a fundamental law of physics. For every action there is an equal and opposite reaction. How the recoil feels is completely dependent on how quickly the energy is transferred to your body and how ...

No the mass of the weapon itself determines how the kick feels, whether it accelerates or jerks. However the power of the kick is all determinant on the time it takes to recoil. Either way the same amount of energy is being absorbed. Muzzle energy is NOT equal to recoil energy. The recoil energy va...

Wait...is that a joke? Are video games banned as well? They better ban rubber band guns next since they resemble weapons of mass murder. Also, i'd be shocked to see Peter Pan books remain legal since they contain sword fights, clearly conditioning Austrailia's youth to be blade toting throat slashe...

we could use a notebook paper penetration method. To be honest, a plastic BB being flung by a mechanical system is not going to go very fast. So we could use a box o truth method simply using sheets of paper. Have we agreed that it will be restricted to mechanical launchers? If only pneumatic and c...

Using a plastic BB doesn't eliminate railguns, it would just require the use of an aluminum or copper sabot. Coilguns could be used as well, but I've not seen one that reaches high enough muzzle speeds to be competitive in such a contest. If anyone can build a railgun or ETG which could compete here...

How about this: fastest projectile without the use of combustion or pneumatics? Projectile being a toothpick... That would include everyone and show ingenuity of the builder That does sound like a very good idea. It involves significant ingenuity not only in developing new propulsion systems, but i...

Very clean build, if not perfectly implemented yet. I'd really like to see more details on that valve after the votes are all in, and ask the owner how those burns on his arms feel. Unfortunately, those little oxygen tanks run out quickly, and are very expensive. Mostly well built and effective, but...

But I was remembering this lecture a cop gave me as a juvenile about some kid who had put a pipe b*mb inside one, electrically ignited it, got hit in the head with a cinderblock chunk and was drooling and wears a helmet all the time... Are you sure he wasn't drooling and wearing a helmet before he ...

What you're seeing here is less likely to be DDT than it is the result of pushing an unsafe building material past its limits. It is well established that PVC is brittle and, being a plastic, has a very low tensile strength compared to that of even mild steel alloys. Consider the case of a very larg...

In most places, the cops require a warrant to enter private property without the owner's permission. To get a warrant, they need to convince a judge that, one, a crime has occurred, and two, that there is reason to believe that you have something to do with it (or pay him a sufficiently large sum of...

A 20 foot long barrel is not going to be successful here - the ranges of the competitive launchers suggest trans-sonic muzzle speeds. Reaching those speeds in a 20 foot long barrel would require accelerations which would surely smash the pumpkin. Hence, the extremely long barrels used by the serious...

If you have the money, the air could be made extremely hot through shock compression, like a springer but with air moving the piston. Simple adiabatic calculations show that almost twice ambient temperature could easily be reached by compressing a sample of air to one quarter of its original volume....

There's nothing against the forum rules about using chemical reactions such as Al/HCl, or phase changes such as off-gassing dry ice as pressure sources. There IS something against the rules about exploding containers with them. The CO2 method has been used before, and works, although it is rather da...

I've seen it accomplished nicely using two lengths 14 gauge solid copper wire wrapped in electrical tape. They are then both passed through a 1/2" brass cap with a 1/2" hole drilled through the top, and the cap is filled with JBweld or some other epoxy. The ends in the chamber are bent toward each o...

A single small strip of aluminum foil should be vaporized by 75J. You will, however, need a very efficient design before you can actually move something out the barrel with that little energy. The average amateur ETG design would be lucky to gently lob an airsoft round out the barrel with 75J input....