...it turns out that Daniel Craig’s biometric Walther PPK/S might be a very good idea. If we truly care about technologies and real-world outcomes, guns ought to be high on the agenda, despite their current politicization. And while the concept of technology fix tends to get a bad rap in most circles, the truth is that under some circumstances they are the best you might hope for if you actually think you can make the world a better place. (Remember, kids: Guns don’t kill ideas—pessimists do.) Technology can solve some problems, as long as a few specific conditions are met. As Dan Sarewitz and Richard Nelson argued in an issue of the journal Nature a few years ago:

“The technology must largely embody the cause–effect relationship connecting problem to solution.” (A palm-print technology would prevent people from firing illegal guns.)

“The effects of the technological fix must be assessable using relatively unambiguous or uncontroversial criteria.” (A drop in the homicide and gun-crime rates would quickly demonstrate how effective the new technology is.)

A similar idea was used in the 1989 Bond film License to Kill; a sniper rifle disguised as a Hasselblad camera outfitted with a palm print identification system prevents anyone but Bond from using the weapon.

An earlier reference to this idea can be found in the Judge Dredd comics from the 1970's; the Lawgiver is a handgun that can only be fired by its owner, making use of the palm print for identification.

More recently, the 2009 movie District 9 has a variation on this idea; the rifles used by the "Prawns" are DNA-encoded so that only be fired by members of that species.

(Alien rifle with DNA identification)

The interface guns from Richard Morgan's 2009 novel Broken Angels appears to do more than just read biometric data; they allow what amounts to information flow between the gun and the user:

The guns, the interface guns, like rage extended in both hands. Biofeed from the palm plates gave me detail. High impact, fragmentation load, magazines full to capacity. The vision I had, outside my fury, found structure in the writhing thing before me and the Kalashnikovs punched solid fire at it. The biofeed put my aim in place with micrometer precision.

However, in spite of all this creative input, gun manufacturers have not really come through with any real-life examples. I did recall this project, the New Jersey Institute of Technology's (NJIT) Dynamic Grip Recognition technology. They received $2M about seven years ago to develop a gun with a biometric locking mechanism that will only work with one owner. The main idea is that the gun's handle would be outfitted with 32 pressure sensors to record your unique holding pattern.

(Dynamic Grip Recognition smart gun project)

Sensors and microprocessors analyze the complex interplay of bones and muscles involved in pulling the trigger, all in a fraction of a second. “The way you hold a gun, curl your fingers, contract your hand muscles as you pull the trigger—all of those measurements are unique,” says Donald Sebastian, vice president for research and development at NJIT.

However, I haven't heard anything more about this technology.