RPG-7: The iconic Soviet weapon used by soldiers, terrorists and militias around the world
The RPG-7 has been used by armies, insurgents and terrorist organisations from all over the world, and has been produced more than nine million times.
The rocket-propelled grenade launcher can be used against a variety of targets, including armoured vehicles, fortified and sheltered positions, helicopters and infantry.
"Even the most basic RPG-7 round from the '60s will penetrate the minimum of 26cm of rolled homogenous armour, which is your basic tank armour," said Jonathan Ferguson, the keeper of firearms and artillery at the Royal Armouries Museum in Leeds.
"So even that today can cause serious problems for a tank, even if it won't knock it out outright."
What is the RPG-7?
Entering service with the Soviet Union in 1961, the RPG is a shoulder-fired, reusable launcher.
Because it is simple to operate and cheap to make, the weapon has found its way into the hands of soldiers and militias from numerous countries including the USSR, China, Bulgaria, Iraq, Iran, Pakistan, Romania and Egypt.
The launcher has an effective range against a moving target of 305m and 488m at a static target.
It was used against British troops in the Gulf War in 1991 and was used to destroy to US Army helicopters in Mogadishu in Somalia in 1993.
Why is this Russian RPG-7 so popular as a shaped-charge delivery system?
Mr Ferguson said: "There are other systems that use a recoilless gun to launch the munition, and then usually a rocket sustainer to send it on its way to the target.
"But the RPG-7 is the definitive take on that, and the most prolific by far and the most iconic by far.
"There is an expansion chamber in the middle to help build up that pressure to get it out of the barrel. This is technically a gun, but it is open at the back. Technically it's a recoilless gun.
"Like a lot of very effective weapons systems, the key is actually in the ammunition.
"The reason this thing is still so relevant is that this old early 1960s bit of steel pipe can be easily upgraded simply by upgrading the warhead.
"You can adapt an RPG-7 to fire a PG-9 round – which is larger and more powerful."

Is the RPG-7 the best of its kind?
The RPG-7 has been used by armies in war zones all over the world, and while it may have been superseded in the Russian army it is still being used in Ukraine.
Its cost-effective nature makes it an easily accessible weapon that can be used effectively against armour and defended positions.
Mr Ferguson added: "In terms of portability, utility and all the other factors, it is almost like PKM and GPMG, Carl Gustaf and RPG-7.
"I almost don't want to come down on one side or the other."
Mr Ferguson was referring to the Soviet-designed PKM and the Western L7A2 GPMG/FN MAG general-purpose machine-guns – both of which have their supporters and detractors.
The West's Carl Gustav recoilless rifle and the RPG-7, both being shoulder-launched weapons systems, also attract fierce debate about which is "best".