The U.S. abandoned laser-guided artillery shells because of high cost and their need for someone to point a laser designator at the target. Laser guidance provides better accuracy than GPS or INS. Despite that Russia stayed with and improved its laser-guided shell technology and now has these shells available in several different calibers; 120mm and 240mm mortars, as well as 122mm, 152mm and 155mm artillery.
The first laser-guided shell was the American Copperhead 155mm shell developed in the 1970s. Copperhead didn’t see any combat until the 1990s and there were no export customers. The Copperhead had too many shortcomings. It was too expensive ($300,000 per shell) and required someone close to the target to use a laser designator to identify the target. All laser guided weapons had problems with fog, mist, and smoke because that diminished the quality of the laser signals. Copperhead failed to gain widespread acceptance, even though it worked. In practice there was little demand for Copperhead except in Russia and China, which developed the tech and still make laser guided artillery shells. Russia developed that tech in the 1980s and China a decade later, before GPS guided GMLRS rockets and Excalibur 155mm shells showed up. The Russians and Chinese copied GMLRS but not the GPS guided shells.
Excalibur shells entered service in 2007 but soon lost most of its demand because of the cheaper, if not quite as accurate, M1156 Precision Guidance kit fuze. This became available in 2011, cost one fifth what Excalibur does and is screwed into the front of any unguided shell, just like any other fuze would be. A similar M395 GPS guidance fuze for 120mm mortar shells was introduced soon after and has been popular (and successful) with the troops.
For the Russians, 120mm mortars are attached to brigades and controlled by the brigade commander. In the U.S. battalions have the 120mm mortar. Russia developed 120mm laser guided shells to increase brigade firepower.
The M395 equipped 120mm shell lands within six meters of the target at 7,000 meters (max range of most 120mm shells). Both these fuzes used the same tech and were from the same manufacturer.
Russia has found that laser-guidance is good enough, especially after the capabilities of their laser designators and laser seekers in the shells were improved in the late 1990s. Russia simply did not have the money to develop something like Excalibur and the Precision Guidance kit fuze. Both required unique manufacturing equipment and skilled workers to manufacture these items affordably and reliably enough to justify their higher cost.
Since the Soviet Union dissolved in 1991 Russia has much less money for developing new weapons. Russia has instead improved its more promising Cold War era weapons and successfully used them in combat, mainly since 2014 in Ukraine and a year later in Syria. Russian troops continue to fight in both these areas.
An example of how Russia gradually improves these laser-guided shell technologies can be seen in what happened to their first laser-guided shell, the Daredevil. This was developed in the 1970s and entered service five years after Copperhead. While the U.S. went on to develop GPS guided shells, Russia continued improving their laser guidance system, which was first developed for their Cold War era 240mm era self-propelled artillery system because some of them had been exported to Syria and proved useful there. This is the 2S4, a self-propelled version of the 240mm towed mortar first seen during World War II as the M240. The 2S4 is the four-ton towed M240 mounted on an armored chassis that also carries the same nine-man crew used by the M240. Both mortars fired the same ammunition, like the 130kg (286 pound) high-explosive shell that contained 34 kg (75 pounds) of explosives. The 30-ton self-propelled 2S4 appeared in the 1970s and remained in production until 1988, with 588 delivered to the Russian army as well as several export customers, including Syria. Russia developed the Daredevil laser guided 240mm shell for the 2S4 during the 1980s. Laser grade accuracy was important for a weapon like the 240mm mortar because weapons of this type have a short range. For 240mm it was normally 9,700 meters. It usually required two or three unguided shells to hit a target. Accuracy was critical because heavy mortars are mainly useful against fortifications or in urban areas. With laser guidance, one shell can destroy a target that might have required two or three and do it with the first shot. This is important because after the first shell, surviving enemy troops quickly take cover.
The 240mm mortar fires a shell that can carry a variety of payloads. The basic high-explosive version can create lethal fragments out to 150 meters. But what has kept the 240mm mortar in use is the anti-fortification shell can go through several meters of earth and concrete to destroy an underground bunker or troops firing from the basement of a multi-story building. One of the incendiary shells can set fire to most of a large structure, which is useful when firing at warehouses or factory buildings. There is a rocket assisted 240mm shell with a range of 20 kilometers using a smaller warhead which achieves acceptable accuracy by using laser guidance. This was one reason why a 240mm laser guided shell was developed. On the downside the 240mm has a low rate-of-fire (one round a minute) despite being breech-loading, rather than dropping the shell down the barrel of most mortars. The 2S4 crew had to use a built-in crane to lift the 130 kg shells up and position them so they could be inserted into the breech loading mechanism.
The Russian 2S4s were also used during the 1980s in Afghanistan, where they provided field testing for the first laser guided artillery shell to enter service; the Daredevil. Both Russia and the United States began developing laser guided shells in the 1970s.
The American 155mm Copperhead entered service in 1982 and five years later the less sophisticated, but workable, Daredevil appeared. The problem with the Daredevil was that its laser detector in the shell had a narrow field of vision, so you often had to fire one or two unguided shells at a target so the forward observer with the laser could be sure his laser beam would be detected by the Daredevil guidance system. This guided shell was used successfully in Afghanistan and in the early 1990s in Chechnya. By the 1990s Russia had also developed a more effective laser guided 120mm mortar system, based on Krasnopol, their version of the American Copperhead. Krasnopol entered service at the end of the Cold War and in the 1990s improved versions were developed that were small enough for 122mm artillery shells and 120mm mortar shells. It appears that this tech is being applied to Daredevil because this 240mm guided shell is now used without the narrow field-of-view restrictions the first Daredevil suffered from. That tech also made a rocket assisted, 20-kilometer range 240mm shell more useful because of laser guidance. Krasnopol is effective on the first shot and the laser designator has a range of five kilometers, meaning the longer range 240mm shell could be used much more effectively.
Both Russia and the Americans found that the more expensive guided shells justified themselves because less ammo had to be used. The expense of buying and transporting a lot of unguided shells to a combat zone is less than the cost of far fewer guided shells. While laser beams and GPS signals can be jammed, the GPS equipped shells and rockets have a less accurate INS (Inertial Guidance System) and recent improvement in INS has made this tech nearly as accurate as GPS.