Non-lethal bullet

Rico's friend Kelley forwards this Esquire article (originally from Popular Mechanics) by David Hambline, about a supposedly non-lethal gub:

A new compact, lightweight weapon will stop a target in their tracks from a hundred meters away without harming them. Nicknamed the Pogojet, it's a radical less-than-lethal design from Jeffrey Widder, senior research scientist at Battelle Memorial Institute in Columbus, Ohio.
The Pogojet (the official name is the Caseless Telescoping Less-lethal System) is unique in that the propellant burns inside the round, pushing on a piston that propels it forward. The action resembles a pogo stick, hence the name. Once the piston reaches its full extent, the exhaust gases can be vented sideways, so the round continues forward at the same speed, or directed through holes in the base of the round like rocket exhaust to give as much extra kick as required. This is the 'jet' aspect of the Pogojet, which Widder compares to the old 1960s Gyrojet rocket pistol.
It's a clever design meant to get around a pesky problem: conventional wisdom says that the non-lethal rounds used to stun suspects need to be big, soft, and slow. Think of the bean bag rounds fired from police shotguns, the 40mm sponge grenades used by the military, and traditional 'rubber' bullets. Their low velocity gives them a shorter range than a thrown rock, a serious disadvantage when facing rioters.
The other challenge with less-lethal impact weapons is balancing effectiveness with safety. A round that travels slowly enough to be safe at point-blank range is ineffective at long range. Increase the muzzle velocity to knock down a target further away and the weapon becomes potentially deadly when used up close.
Widder's challenge was to find a way of varying the muzzle velocity depending on the distance to the target, so that the projectile always hits in the sweet spot of between 77 and 87 meters per second. His final design uses a small .50 caliber weapon firing a hard projectile that uses that gas venting strategy to hit the target at optimal speed. This variable speed makes the Pogojet safe at short range and effective at long range. Widder says it will be effective at a hundred meters, far further than any existing kinetic round.
"Once the gas comes out it can be throttled," said Widder. "The technical challenge turned out to be remarkably simple. Once I'd figured it out I didn't know why I found it so difficult."
The Pogojet will use a laser rangefinder, technology that already exists for small arms, but mainly used with military grenade launchers. The Pogojet will interface with a rangefinder to ensure that the right muzzle velocity is automatically selected without any manual control. Building the interface is one of the next steps in the project. But the key element, the variable velocity system, has already proven highly reliable.
Widder's design has another advantage in that it produces enough pressure to work as a semi-automatic, unlike the pump-action bean-bag shotguns. Unlike other less-lethals, the Pogojet can be fired as rapidly as needed, so the shooter can get off another shot if they miss the target.
The piston arrangement also means even a very short barrel is enough for high velocity and accuracy, making the Pogojet more compact than the alternatives. Widder imagines the weapon fitted as an under-barrel extra to an M4 carbine, giving soldiers a simple, long-range, multi-shot alternative to lethal rounds. The Pogojet might also be used separately as a pistol, without the rangefinder and set to the lowest velocity. It could still be effective out to fifty meters, compared to twenty meters maximum for a bean bag gun and even less for a Taser, giving cops an easily portable alternative.
Most non-lethal kinetic rounds are designed to flatten on impact and spread the blow over a large area. This improves safety by minimizing the risk of a penetrating injury. This also explains why such rounds tend to be of a large caliber: small ones can go through an eye socket with serious consequences.
Widder takes a different approach. His round is spin-stabilized and has a flat trajectory, so it can be aimed accurately. Shooters are trained to aim lethal rounds at the target's center of mass, and the Pogojet is fired in the same way. (Widder says other non-lethal rounds are supposed to be aimed at the thighs or buttocks.) The Pogojet bullet does not deform on impact, but delivers all its energy over a smaller area. Widder says that it produces a high level of pain with less kinetic energy than the traditional approach. "It's like a bee sting. It' s only over a small area, but it is intense enough to be effective."
The small rounds might seem dangerous compared to more traditional, larger-diameter non-lethal weapons, but Widder argues that a high level of fire discipline is always needed. Unlike other kinetic weapons, the accuracy of the Pogojet means it will hit where it is aimed. "The greatest risk of severe injury or death occurs from impacts to the head, face, or neck of the intended target or a bystander, " Widder said. "The use of more accurate weapons with disciplined fire can substantially reduce the likelihood of this unintended consequence."
The next stage of Pogojet's development will be to build the rangefinder interface and the semi-automatic mechanism, as well as replacing many of the metal components with plastic. If it's as good as Widder says, then the weapon could some day offer a new option for police and members of the military faced with situations where normal firearms would constitute excessive force.

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