December 1, 2011: It had to happen. An American firm has come out with a battery pack that fits under an M-16 type weapon and supplies power to multiple devices attached to the rail on top of the rifle. If this RIPR (Rifle Integrated Power Rail) device is widely adopted, it would mean more reliable power for rail mounted items, and the ability to build them lighter and smaller (by leaving off the batteries).
In the last two decades, an increasing number of accessories have been developed for military rifles and machine-guns, and most of them would not have appeared were it not for the development of the "Picatinny Rail." This is a standard for a metal rail, with crosswise grooves, that make mounting accessories (scopes, lights, and so on) easy to do. Just snap them on, or tighten a few screws. The Picatinny Rail is a development of the Weaver Rail, which has been around since the 1930s. Items built to attach to a Weaver Rail can be attached to a Picatinny Rail, but not vice versa.
The war in Iraq and Afghanistan has created a demand for weapons accessories, and caused hundreds of new items to be invented for attachment to weapons via the Picatinny Rail. Such rails were originally found just on the top of the rifle (forward of the breach), but are now often found underneath the barrel as well, forward of the magazine. Many of these devices rely on battery power, thus the need for something like RIPR. Most people have never heard of the Picatinny Rail, but anyone who handles an assault rifle or light machine-gun, knows all about them, and can't imagine going into combat using a rifle without rails. If RIPR becomes widely used, there will be fewer problems dealing with the battery needs of several rail mounted accessories.