Filipino soldiers, fighting Islamic terrorists (Abu Sayyaf) in the southern Philippines, were surprised to encounter fire from what appeared to be Russian made RPGs (Rocket Propelled Grenades). While a common weapon in Iraq, Afghanistan and many other parts of the world, the Filipino military stopped using them over 30 years ago. Since local rebels and terrorists get most of their weapons from the military (off dead soldiers, or corrupt troops selling to anyone), this was a surprise. There had been a few encounters between Filipino troops and Islamic rebels using RPGs in the 1990s. Back then, the RPGs had come from Vietnam, and were supplied to Filipino rebels by arms smugglers. But this supply dried up, and the RPG launchers were soon out of ammunition. But now Filipino troops were getting hit with RPG shells again. Technical experts examined the evidence and concluded that the RPG shells were made by local craftsmen. This was not an impossible task, as it has happened in other parts of the world.
The RPG was developed from World War II "bazooka" type weapons and introduced by the Russians in 1961. The common RPG 7 launcher weighs about 17 pounds, with most grenades weighing five pounds each. American tanks and M-2 Bradley infantry vehicle (with additional appliqué armor) are mostly invulnerable to RPG fire. During the Iraq fighting, it was common for most of the armored vehicles in a unit to be hit at least once by an RPG round. The real damage from RPG fire was the fragments from the exploding grenades. Even the anti-tank round (the most common fired by the RPG) would throw out wounding fragments for 10-15 feet (about 4 meters). These fragments rarely killed, but troops were often wounded in the arms, legs and face, and often put out of action for a while. But most armies, and irregulars, like the RPG because it is cheap, easy to use and very effective against troops lacking protective vests and helmets.
The most common RPG ammo is the anti-tank rocket and these go for $50-100 each. This adds up, as you have to fire a dozen or so rounds to develop some accuracy. Unlike the launchers, RPG ammo doesn't get cheap, unless some wealthy nation is flooding an area with it, because the ammo gets used up and the launcher does not. It's not known what Abu Sayyaf was paying for their hand crafted RPG rockets, but it had to be enough to justify the maker to scrounge up the components and craft the individual rockets.
Without much practice, a user can hit a vehicle sized target most of the time at ranges of 50-100 meters. As an operator fires more rounds, he becomes capable of hitting stationary targets at up to 500 meters, and moving targets at 300 meters. It's this last skill that has made the RPG dangerous against helicopters. Irregulars also like using the RPG as a form of artillery. Get a bunch of RPGs firing at the same area say, a kilometer away, and you will do some damage to any people walking around. The rather more rare anti-personnel rockets will spew out fragments up to 30 feet or more.
While many users are disappointed at the effectiveness of their RPGs against well protected (like American) armored vehicles and troops, the weapon is still very useful against just about every other military force in the world. And many irregulars spend a lot of time making war on civilians, where the RPG is a terrifying weapon. Firing an RPG at the wooden hut that a hostile (to your cause) family lives in, sends a message, even if it doesn't kill anyone in the building.