New Tech Puts the Brakes On Bullets Fired From Police Sidearms

Zothecula writes: Police officers are trained to shoot for the center of mass, not necessarily to kill, but to stop – although the end result can often be one and the same. "The Alternative" is designed to give officers a less lethal option in the form of a clip-on "air bag" for semiautomatic pistols that reduces the velocity of a standard round to make it less lethal. At the front of the bright orange carrier is a hollow sphere made of a proprietary alloy that catches the bullet and firmly embeds it as it leaves the barrel. The ball and bullet fuse, slowing the round by 80 percent. At this speed, the ball-encased round is less likely to penetrate flesh, but it will transfer enough kinetic energy across a wide surface to knock a suspect down with less chance of a lethal outcome.

Comments

Bullets don't knock people down

[SpaceManFlip]

This is stupid because a normal bullet doesn't even have the kinetic energy to knock over a person. That is all Hollywood make-believe.
There's a whole series of tests done on Mythbusters that debunked the concept.
So these bullets are going EVEN SLOWER than normal ones, and it's supposed to "knock down" a person?
Think about this: a typical 9mm round will be 115 grains or 124 grains in weight. One grain is 1/7000 of a pound. We're talking about a projectile going in the ballpark of 1000 fps that weighs only about 0.0177 pounds for the 124 grain bullet. There simply is no knock-down potential.

Now, on the other hand, if you are seriously injured by one of those projectiles, you'll probably fall over in pain. Or you might also just fall over dead.

Re:Newtonian physics

[Firethorn]

Are you accounting for the extra mass of the airbag device? Going by physics:
It's momentum is 370*7.5 = 2775 gm/s
2775/75 m/s = 37 grams for "the alternative" + bullet, meaning the sphere should weigh ~30 grams.

37 grams@75m/s = 208 J

BTW, when I calc your figure I come up with 42 J, not 21.
7.5 grains* (75 m/s)^2 = 42.2 J

By the way, I looked up Bean bag rounds.
40 grams@70-90 m/s, which impacts ~6cm^2.

Seems roughly equivalent to me. The ball is right in that velocity zone, a little light by my estimate, but it's likely to impact a slightly smaller area. Might just work.