Slashdot Mirror
Guy Creates Handheld Railgun With a 3D-Printer (engadget.com)
turkeydance writes: Using a combination of 3D printing and widely available components, David Wirth built a functioning handheld railgun that houses six capacitors and delivers more than 1,800 joules of energy per shot. So far he has tested the gun using metal rods made of graphite, aluminum and copper-coated tungsten. David has shot projectiles at over 250 meters per second in tests.
AK-47: 715 m/s
.44 Magnum: 360 - 450 m/s
Black powder musket: 120 - 370 m/s
If only criminals have guns it will be damn easy to identify them and lock them up.
True-ish, but the devil is in the details... you'd probably need a lot more law enforcers to be able to do that. AKA a "police state".
Sweden respectfully disagrees.
it's in my head
If only criminals have guns it will be damn easy to identify them and lock them up.
True-ish, but the devil is in the details... you'd probably need a lot more law enforcers to be able to do that. AKA a "police state".
I, for one, prefer a society were it is generally acceptable that individual members take some responsibility for their own well-being. I always thought the liberal mindset is all about the individual and his liberties.
The rest of the developed world with its massively lower murder rates disagrees as well as Sweden.
Yes - though not at the level of the one in TFA and probably, for the foreseeable future, only in the realm of large naval guns (and possibly - slightly further down the line - guns mounted on tanks or large aircraft).
With a traditional naval or tank shell, much of the damage comes from the explosive contents of the shell (which tend to be quite sophisticated in their design these days). The downside of this is that the ship or tank ends up carrying a substantial quantity of explosive material, just waiting to be set off. Magazine explosion is a particular danger for ships.
Railguns, by contrast, fire inert slugs. The damage comes from the (much) higher velocity at which the slug is fired, which translates into much higher kinetic energy transfer on impact. This means that the ammunition tends to be smaller (so you can carry more of it) and safer. The higher velocity also has significant potential benefits in terms of accuracy.
The US Navy is currently conducting real-world tests of railguns on ships and there has been a lot of progress over the last few years. The challenges include the high power requirement and the need to replace rails regularly (due to the extreme stresses associated with each firing), which can substantially harm rate of fire.
Practical handheld railguns which offer significant benefits over existing firearms are still a long way off (if, indeed, they ever happen). The one in TFA has a muzzle velocity which is at the low end of the range for a "traditional" firearm, with significantly lower convenience (and some quite worrying looking safety issues).
Umm, the primary round shot from a tank gun is APFSDS (Armor Piercing Fin Stabilized Discarding Sabot). It's a big dart. No explosive at all.
"I do not agree with what you say, but I will defend to the death your right to say it"
"Uncontrolled immigration", yeah... Another one that has drunk the cool-aid of the now-said-to-be-reformed-racist extremists. The likes of you are more a part of the problem than the solution.
I used to live in one of the said "ghettos" for the first 25 years of my life, and believe me, the crime rate there isn't higher than in the central parts of the big cities, quite the contrary. Also ghetto is a very strong word, so I guess that you have never set foot in one of these areas, nor seen a real ghetto, or else your retorics would be quite different.
The problems in Sweden are with criminals, not immigrants per se. Anyone alienated from society have to find new ways to get by and most does in peaceful and meaning ful ways, forming their own groups within society (sad to see competence wasted this way because we are too stupid and stubborn to let good people find good work). A few turn to crime, but from the criminals I have met more have had "pure" swedish background than being first or second generation immigrants.
But making up "facts" to support one's twisted world view is standard practice within these extremist circles, so I am not surprised at all.
That's not a bad guess, but not really true, for four reasons.
First, there is no "moment of detonation", powder doesn't detonate*, it burns quickly, producing gas. It's a lot of gas in a small space, so it's under pressure and that pressure pushes the bullet out. The powder continues to burn as the bullet moves down the barrel and even -after- the bullet leaves the barrel, producing muzzle flash. In pictures you may have seen the "fire" coming out of the muzzle. That fire is burning powder, meaning it's still burning after the bullet is gone.
To look at it from another perspective, imagine a firecracker on a stick. When the cracker blows, the stick doesn't get shot "backward" toward whoever lit it. The recoil exists because (and while) the bullet and gas is being propelled down the barrel. So the duration of recoil force to the slide is the same as the duration of pushing the bullet down the barrel, equal and opposite at any given instant.
Third, slide -momentum-. The mass of the slide means that the recoil force increases the momentum of the slide, and the hand feels the force as you resist the slide's recoil - meaning the hand or other mount feels the recoil until the slide stops, after the bullet has hit the target.
Lastly, the slide -move- relative to the frame (and hand or other mounts) against a spring. Since the slide is pushing on the spring, and the spring pushing on the frame, it's actually the pressure of the -spring- that pushes on the frame. Therefore the mount experiences only as much recoil as the resitance of the spring at that portion of its travel.
* Some powders contain ingredients that -could- detonate if they were pure, but they are mixed with much slower burning components in order to slow them to a conflagration.
Posting anon since I work with the Dahlgren EMLF (Electro-Magnetic Launch Facility)
I'm not going to comment on specs, but the current test launchers (to my knowledge) does not require rebuilding every shot (even with higher MJ launches). They did about 6 years ago. The navy's final launcher also is going to fire at rates over 9 / min, which puts a lot more load on the rails and power supply system (and other things). This is part of why it's taking awhile to develop. Compressing a building's worth of equipment down to fit in a ship is also non-trivial.
It's not particularly expensive to shoot. I have been told there are some times we do shots as opposed to using modeling because it's quicker, cheaper, and is better data. The missile development people would kill for something like that.
There are some issues with rail wear, but a round only ever gets fired once, so the electrical destruction of the round that occurs only has to not affect the aerodynamics of the round for that shot.
This is 100% fake.
http://o.aolcdn.com/hss/storag...
1: That's not handheld.
2: That's a CO2 tank.
He's built a paintball gun and put a bunch of shit on it, then added sparks at the end of it.
1800 Joules is way over a fucking 44 magnum (1300-1500). Yet if you look at the videos posted, you can see that when he fires at some particle boards nothing fucking happens. The "article" original claimed it was 3,000,000 Joules. LOL!
If you read the video descriptions on Youtube, he claims:
WXPR Test 3 - 1" long 0.25" aluminum sabot (1.1g total mass). 1.6kJ caps, 500 psi injector. 36" distance to target: angled 3/4" plywood board with 1/4" mild steel backplate. Made a 1/2" deep indent in target and bounced off. Speed was above 250m/s.
Successful proof of concept for repeatable shots on the same set of rails.
So, 1600 J, not 1800. And that tank at 500 PSI is an "injector"? LOL! It's an air gun with some capacitors for no reason!!
His latest video involves shooting a cantaloupe, because everyone laughed when he couldn't penetrate plywood. He claimed they were "steel backed" plywood boards, but he still barely put a dent in them.
Here's the cantaloupe: https://youtu.be/t0vCiafjUy8 He allegedly fires at around 1300 J according to his own LCD display. There's an odd cut at 1:51 in the video as well, so I have no idea what he's actually doing. (Watch from 1:49 to 1:52 at 0.25 speed to see the cut). You can watch the shot in slow mo too.
Here's a 44 magnum shooting a watermelon: https://youtu.be/dYtfq8KdlnE A 44 magnums runs at 1300 J to 1500 J. Do they seem at all comparable?