After more than a decade of development effort, by several different companies, there are now several guided versions of the 70mm air-to-ground rocket. Developing a guided 70mm rocket took so long because the manufacturers underestimated the technical difficulties of getting the laser seeker and flight control mechanisms into that small a package, at a weight and price the customer could afford. The price of the new 70mm missile is about $30,000 each. This is typical for these weapons and about a third less than a smart bomb and less than a third of what a Hellfire missile costs.
The guided 70mm rocket is used against targets that doesn't require a larger (49 kg/108 pound), and more expensive (over $100,000), Hellfire missile but still needs some targeting precision. In tests the APKWS hit within a meter (a few feet) of the aiming point, about what other 70mm missiles are capable of. The 70mm missile makes an excellent weapon for UAVs, especially since you can carry more of them. The launcher for carrying these missiles is designed to replace the one for Hellfire but can carry four missiles instead of one.
All these 70mm guided rockets are basically 13.6 kg/30 pound 70mm rockets, with a laser seeker, a 2.7 kg (six pound) warhead, and a range of about six kilometers. Laser designators on a helicopter, or with troops on the ground, are pointed at the target and the laser seeker in the front of the DAGR homes in on the reflected laser light.
The 2.75 inch (70mm) rockets were developed during World War II, as an air-to-air weapon for use against heavy bomber formations. The Germans had developed a similar and very successful weapon (the R4M). Before long it was noted that neither the Japanese nor the Germans had any heavy bombers, so the U.S. 70mm rocket was switched to air-to-ground use. Actually, the 70mm rocket was retained for air-to-air use into the 1950s, but it was never successful in that role. The 70mm rocket became very popular in the 1960s, when it was discovered that the weapon worked very well when launched from multiple (7 or 19 tube) launchers mounted on helicopters. The 108-138m cm (42-55 inch) long rockets could be fired singly or in salvoes and gave helicopter pilots some airborne artillery for supporting troops on the ground. There are many variations in terms of warheads and rocket motors. Some versions can go over 10 kilometers.
Apparently the orders for 70mm guided missiles have not been forthcoming because the Hellfire was doing the job and there just wasn't a big demand for a smaller missile. Several smaller missiles have been developed, and one of them, the Griffin, is being used over Pakistan and Afghanistan on American UAVs. The smaller Griffin is an alternative to the Hellfire II (48.2 kg/106 pounds with a 9 kg/20 pound warhead and range of 8,000 meters) because it weighs only 16 kg (35 pounds) with a 5.9 kg (13 pound) warhead. Griffin has a pop-out wings, allowing it to glide, and thus has a longer range (15 kilometers) than Hellfire. UAVs can carry more of the smaller missiles, typically two of them in place of one Hellfire.
The marines believe that a mini-Hellfire, in the form of their APKWS II, has a role on the battlefield and plan to keep using it in combat. The APKWS is a lot cheaper than Hellfire or Griffin and for the marines cheaper is seen as better.