The U.S. Marine Corps has saved over half a billion dollars in the last four years, by using indoor electronic firing ranges. IMST (Indoor Simulated Marksmanship Trainer) has cost over $200 million, but the savings in ammo, wear on weapons, and running outdoor ranges were much larger. Nearly 200,000 marines have undergone marksmanship training using IMST. Unlike the similar U.S. Army EST system, IMST is wireless. A special magazine contains gas that provides a realistic recoil and a wireless radio device connects the weapon to the targets displayed on the screen and records how accurately the electronic rounds were fired.
Devices like IMST and EST have boosted the shooting skills of troops, while reducing costs. This gives American riflemen a big battlefield advantage. In most armies, the troops rarely fire their rifles. Ammo is too expensive (given the meager military budget). When there is combat, the troops are issued bullets, which they fire very inaccurately. Against a better trained foe, this leads to quick defeat. Happens all the time. But now cash strapped armies can train their troops to be effective marksmen without spending a lot of money, by using simulators.
The U.S. Army pioneered this with their EST (Engagement Skills Trainer) 2000 system. Each of these consists of a movie theater size screen (but at ground level, not raised) with back projection target situations displayed as interactive movies. The troops use rifles, pistols and machine-guns that are actual weapons, but modified to fire "electronic bullets", and, via a thin cable, use a pneumatic system that provides recoil as well. There is a sound system to depict the sound of the weapons firing, as well as a computer controlled tracking of ammo fired, letting users know when they have to reload.
Because EST and IMST are simulators, they capture a precise record of exactly where the shooter's weapon is aimed, how well the shooter pulls the trigger, and how long it takes to find and fire at the next target. This enables instructors to much more rapidly detect problems troops are having, and correct them. Tests have shown that you can take people with no weapons experience, put them through four hours of simulator training, and take them to a rifle range, and they will be able to fire accurately enough to exceed military requirements. Studies have shown that troops trained with a simulator gain as much marksmanship skill as those using live ammo.
In addition, a simulator like this can be used for training troops in ways that are impractical using live ammo. For example, when used for "shoot/don't shoot" situations, the appropriate visuals (either an enemy soldier, or a civilian) are shown on the video screen. Soldiers train in a group, positioned as they would be in a real situation. The scenario then plays out, allowing the troops to practice when they should shoot, and when they should not. Training can be for day or night scenarios, and for a wide variety of situations.
These systems are sometimes built into standard shipping containers, so they can be moved around to where they are needed. The more useful of these "sims in a box" are the "encounter" and "convoy" sims. The encounter sim puts troops in a container containing video screens on three sides that portray an encounter between troops and foreign civilians (as they would encounter on patrol or manning a checkpoint). The troops are then allowed to deal with typical problems encountered in situations like this. While not combat (although some gunfire can be introduced), it is extremely useful training for troops headed for the combat zone.
A nation like China can build EST like systems for less than $100,000. But the Chinese have traditionally spent more time training their infantry to move quietly and pay attention to camouflage. These are important combat skills, which most nations do not spend a lot of time on. But when it comes time to shoot someone, you have an edge if your troops are accurate. China has been building aircraft and vehicle simulators. Operating warplanes and tanks is very expensive, and simulators are a much cheaper way to give operators useful experience.
In the West, there has been a lot more development of non-combat simulators in the last few decades. This has pushed total worldwide simulator sales to over $8 billion a year (out of total defense sales of $1,100 billion). Operators of electronic equipment are much more effective if they have lots of experience. But actually using their radars, sonars or complex missile systems is also very expensive. So simulators provide essential experience inexpensively.
Most nations can appreciate the need to train their pilots, ship crews and electronics operators to be better at their jobs. But ground combat troops are another matter. In most nations, the army exists mainly to protect the leadership from the population. The troops tend to get frequent training for riot control. Issuing them a lot of ammo is not considered wise, as soldiers in these countries are not considered particularly reliable. So even in military affairs, political expediency trumps everything else.