The XM25 autocannon is neat. Absolutely nobody denies this. It's also pretty useless, because any insurgent who engages security forces in a conventional gun battle is going to die. Nine times out of ten, they're dead; if by airstrike or just being outflanked and outgunned.

They know this, which is why for the last nine years, the weapon of choice used by the other side has been the IED or the suicide bomb; where high tech weapons like the XM25 are rendered entirely useless. While it's nice to see the Economist running an advertisement for Alliant Techsystems in their magazine, the XM25 will actually do very little to win CI wars.

Saving gas is important. If you're shipping gas or ammo by truck, you're creating targets for IEDs. Our casualty rates would be significantly higher if we couldn't use foreign drivers. The DARPA self driving car challenge was a response to the IED turkey shoot that's our supply line. At least we can avoid casualties.

The howitzer only offered "a few more tactical options", mainly being the ability to lay down accurate indirect fire whilst still being able to offer direct fire and defensive fire.

I mean why bother inventing gunpowder or rifling or any other weapons when an arrow killed people too. I mean sure the rifle was more effective and less competent soldiers could use it skilfully, but what was the point when we already had bows and crossbows?

So why bother inventing an accurate method of firing a frag round at 500ft when the M203 has a max range of 400ft and effective fire at only 150ft. Granted the AK47 is only effective at 250ft, but that still means the soldiers will be spraying and praying with grenade fire.

The whole point of making a weapon more accurate and effective is to increase the enemy combatant losses whilst decreasing civilian losses and soldier risk.

Additionally, they are working VERY hard to improve IED detection, and in fact are making quite a bit of headway in that regard. The same goes for every other issue you raised.

There's no reason you can't improve offense while simultaneously improving defense.

The US will have a significant advantage in developing jamming systems against these types of rounds.

The US isn't afraid of some Afghan insurgent living in a cave from developing a countermeasure against these new munitions. They're afraid Russia or China will be capable of developing a countermeasure. The rounds are worthless, or potentially dangerous, if you can cause premature detonation.

The fact that this particular weapon isn't useful in an IED attack doesn't mean that it's not useful for what it's designed to do. You seem to be under the impression there's no shooting going on in A-stan. This is definitely not the case.

It will certainly change the way soldiers will fight, but the advantage is that the insurgents and less developed nations won't have the technology and likely won't have the understanding of it. Everyone knows grenade launchers lob the round. However, it's going to be very different when it's got the range and the level trajectory of a rifle.

Suppose the bullet leaves the muzzle rotating at 300,000 RPM (quite reasonable for a rifle). That is 5kHz. It's easily within the capabilities of a Hall Effect sensor to measure a 5kHz rotation and so I'd make the very centre of the bullet contain a free rotating magnet. The rifle itself sets the magnet spinning at some known rate opposite to the rifling. When the bullet leaves the rifle it is able to measure the time between detections of the magnet and given the known rifling, the known magnet rotation speed it would be able to calculate rotations.

Alternatively, the inner magnet could be spinning in the same direction as the rifling but faster and detect complete rotations of the bullet. Either way I think Hall Effect + spinning magnet at bullet core would work.

Also, 5kHz is well within the operating range of a micro controller so this wouldn't need much computer power. Lastly the article says that the weapon is accurate at 500m and that the shrapnel kills everyone within a few meters. Also says that the soldier estimates the target distance.

That sounds like there's plenty of room for the measurement to be not too accurate. Suppose 'several meters' is 5 then you can get away with an error of 1% or so.

So, it seems to exist a correlation between the RPM of the projectile and its velocity over wind's influence that guarantee a linear calculation over the RPM of the projectile.

If the target is behind a rock, the soldier uses a laser rangefinder built into the gun to get the distance to the rock, and then inputs into the gun "the target is 2m behind the front of the rock". So, unless the explosion radius is small, the soldier has to make sure the bullet explodes behind whatever is between the rifle and the target.

Given that this is basically an ultra-fast artillery device, the tech in this gun more likely represents a natural evolution of applied external ballistics (http://en.wikipedia.org/wiki/External_ballistics) - incidentally this is a purpose for which the ENIAC was designed. I bet the magic has more to do with being able to collect and characterize environmental data through sensors and plug these meaningfully into Ballistic models.

http://en.wikipedia.org/wiki/Challenger_2

Read the comment by Steven Den Beste, who explains the situation pretty well (aside from getting the HESH acronym wrong):

http://www.professorbainbridge.com/professorbainbridgecom/20...

Also... aren't exploding bullets illegal under the Hague convention?

In that case, losing the ability to use those weapons was deemed to be outweighed by the consequences of having to deal with them being used on you. Also, since they could be potentially huge and unpredictable force multipliers, it made war all the more predictable, which is good from their perspective.

Long story short, nearly all rules of war exist because they are beneficial to abilities of the parties to conduct war. The rules do no exist to make killing fair. They exist so that parties may conduct war in a way they agree with.

That actually makes perfect sense. Although I find it rather disturbing.

http://en.wikipedia.org/wiki/Expanding_bullet#Law

and note that domestically governments do not have to obey even the most basic "rules of war" when they set police against their own people

Secondly the other parts of the convention do not talk about war as a set of specific circumstances (e.g requiring declaration of war) but just hostilities regardless on how they originated.

So by skipping the declaration of war one simply breaks one additional part of the convention, the one mandating the declaration.

Snipers are force multipliers ~ http://en.wikipedia.org/wiki/Force_multiplication

Also a better rifel is less prone to jamming (this is why SF's prefer the piston version of the M4)

The only things keeping this going are racism, ignorance or misperception fueled by propaganda, and a sick, inhuman and outdated Social Darwinism.

We just cannot permit criminals and thugs to continue to have control.

The military sure do like to make themselves seem important. Super secret alien assault rifles being attacked by unspecified hackers from unknown locations. Yep, better keep funding new and exciting ways to kill people.

Maybe there's still some minuscule effect that can be detected, though. The sections on Magnus force in http://www.nennstiel-ruprecht.de/bullfly/index.htm seem to suggest that this is the case. But now I'm not so sure it's as simple as counting the number of periods of oscillation from the accelerometer.

IANAIBOEP (I am not an expert in ballistics or even physics)

When the round is fired, it will experience a huge acceleration from the propellant along its axis plus a very large rotational acceleration as the rifling spins the round from 0 revolutions per second to a large number of revolutions per second.

Once the round leaves the barrel, it is falling at a constant acceleration (9.8m/s, freefall, 0G, "weightlessness"), so it will not be able to measure the earth's gravitational force. It also will be spinning at a constant rate because there is no outside force increasing or decreasing the spin rate, thus no rotational acceleration. While there will be acceleration due to the centripetal effect of the rotation, that acceleration is constant and thus not usable with an accelerometer for counting revolutions.

That's different than measuring the change in acceleration.

(http://en.wikipedia.org/wiki/Accelerometer)

Users usually calibrate the device at rest to get a good estimate of G so that it can be subtracted from accelerations measured later. Is that what you mean?

Perhaps measuring the negative acceleration caused by air friction could give you a velocity estimate (the velocity-to-friction function is probably non-linear). But this may vary a bit with air density, temperature, etc.

I'd be interested to see how it's done. My bet is that it's not directly measuring a near-impulse acceleration.

I'm more interested by the mechanism that programs each projectile's detonation distance. That seems like the tricky bit...

Since it's in the chamber protecting it from external sources of interference / attack (e.g. programmed to explode at the end of the muzzle) should be easy to protect against physically. I guess you could do it with some mechanically retractable pins or something, but electrical contacts and the inside of a bullet chamber don't seem like the sort of thing that should go together to me. You'd need to clean them constantly.

If not, I can easily imagine a "bullet jammer" gizmo that broadcasts a retargeting command. "Sorry, little grenade, you have another thousand meters to go...."

Just wait 'til your local police get these for "domestic terrorism crowd control" (aka protesters) with the shrapnel replaced by "less lethal" rubber bullets while drones fly overhead for more accurate targeting.

Oh it would never happen, right? What if a congressman owns stock in the company?

http://influenceexplorer.com/organization/alliant-techsystem...

Enemies will simply adapt to new weapons they face. Much like a bucket of paint would be quite effective against and remote control mini tank.

Whilst the engineering feat is impressive, it is still important to note that at the receiving end of such ingenuity is a writhing half dead corpse so it is with hesitation I would ever celebrate such innovation.

The tools are horrible, because war is horrible. If you're opposed to their use, you need to act at the political level (to stop unnecessary war from happening) or the strategic level (to win the conflict in a way that does not require direct, physical confrontation)