It was recently announced that 2,000 of the AGM-176 Griffin missiles had been produced so far. Since entering service in 2010 the Griffin has been pitched as a replacement for Hellfire. But only SOCOM (Special Operations Command) and the CIA have bought many, and in much smaller quantities than Hellfire, which weighs three times as much as Griffin. The U.S. Army remains the main user of Hellfire but because of frequent use on helicopter gunships. Because of the growing use of larger UAVs (like Predator and Reaper), the air force and CIA have become heavy users as well.
It was believed that smaller missiles would become popular because more could be carried and these (like 70mm guided rockets and Griffin) weapons contain even less explosives (limiting casualties to nearby civilians). But Hellfire remains the missile with the track record that you can always depend on and the smaller missiles just never caught on.
In service since 1984, the American AGM-114 Hellfire missile has not only proved enormously useful in the war on terror, it has also defeated numerous efforts to replace it with something better. It didn’t help that an improved Hellfire, Hellfire II, appeared in 1994 and over 30,000 have been produced so far. These have been the most frequently used American missiles for over a decade, with over 16,000 fired in training or (mostly) combat since 2001. A growing number of these Hellfires are for foreign customers. Hellfire missiles cost about $100,000 each depending on warhead and guidance system options. Britain produces a Hellfire variant, called Brimstone which is unique mainly in that it can be fire from jets. This version has become very popular as well.
Hellfire was originally designed for use by helicopter gunships against masses of Cold War era Russian tanks. That never happened, except in Kuwait during the 1991 war against Russian tanks owned by Iraq. Hellfire was quite successful in Kuwait. With the end of the Cold War the Hellfire seemed destined for the history books, as just another missile that worked but never distinguished itself. This all changed in 2002 when the CIA first used a Hellfire fired from a Predator UAV to kill a hard-to-find terrorist. The U.S. Air Force wasn’t really interested in this sort of thing and the CIA used its own money and authority to buy Predator UAVs and arm them with Hellfires. It quickly became apparent that the air force was wrong about UAVs and, well, the Hellfire was an army weapon used on helicopters and the air force never considered such a combination of UAV and missile useful for anything. The army soon found that Hellfire was an excellent weapon for supporting troops in urban areas or when going after terrorists anywhere.
The CIA was also the first to use smaller missiles like the Griffin on UAVs. This enabled targets to be destroyed with less risk to nearby civilians. The Griffin was created as an alternative to the Hellfire II, which weighs 48.2 kg (106 pounds) and carries a 9 kg (20 pound) warhead and has a range of 8,000 meters. In contrast, the Griffin weighs only 16 kg (35 pounds), with a 5.9 kg (13 pound) warhead which is larger, in proportion to its size, than the one carried by the larger Hellfire missile. Griffin has a pop-out wings, allowing it to glide, and thus has a longer range (15 kilometers) than Hellfire but takes much longer to reach the target. UAVs can carry more of the smaller missiles, typically two of them in place of one Hellfire.
Even before Griffin hit the market there were several firms offering 70mm rockets reconfigured as guided missiles. The result was basically a 13.6 kg (30 pound) missile with a laser seeker, a 2.7 kg (six pound) warhead and a range of about six kilometers. The U.S. Marines have adopted these for use on their helicopters and the results have been satisfactory. What won the marines over was price, as the marines are always short of cash. Several European and Israeli manufacturers came up with similar smaller missiles, but none really proved all that superior to old reliable; the Hellfire.
All these weapons use laser designators on an aircraft, or with troops on the ground for guidance. The laser is pointed at the target and the laser seeker in the front of the missile homes on the reflected laser light. This system enables the missile to hit within a meter or so (2-10 feet) of the aiming point. On the downside fog and clouds distorts the laser and makes it unreliable.