Ridley Scott has revealed actor Idris Elba thought he'd really been shot in American Gangster after the director tricked him with the recoil - after safety-conscious Scott had insisted on not even having blanks in a gun. Scott, 83, said the weapon used on the set had a solid filled-in barrel, with no bullets in it, for the scene where Frank Lucas, a mob boss's right-hand man, played by Denzel Washington, puts a gun against the forehead of Elba's character Tango. Elba was acting out a scenario like the one that had earlier tragically killed actor Jon-Erik Hexum, who put a gun against his own head and fired - but whereas Hexum had a blank in his gun, Scott didn't even have blanks in the gun for Elba's fake shooting. 2007 film: Ridley Scott has revealed actor Idris Elba thought he'd really been shot in American Gangster after the director tricked him with the recoil - after safety-conscious Scott had insisted on not even having blanks in a gun But to add realism and draw a reaction from Elba, Scott told him to lean his head against the barrel - so he would be shocked by the recoil in the scene from the 2007 film. Scott said: 'He's in the cafe and he says "just stay here" and he goes out and all his brothers are watching, and he goes down the street, and Idris Elba is standing there saying "hey, what are you going to do, shoot me Frank, go on, shoot me Frank in front of all these people".' 'And he just goes boom and shoots him on the spot. 'What happened was, I said to Idris "listen, when he puts the gun to your head lean on the gun" - because by the way this is a gun with a solid barrel, there is no aperture, I would never risk it - but when you pull the trigger there's a recoil, there's no blank, nothing. Candid: Scott, 83, said the weapon used on the set had a solid filled-in barrel, with no bullets in it, for the scene where Frank Lucas, a mob boss's right-hand man, played by Denzel Washington, puts a gun against the forehead of Elba's character Tango 'So I said 'I want you to lean on the gun'.' The movement from the gun pressed against Elba's head made him instinctively fall to the ground thinking he'd actually been shot by a bullet from Washington. Ridley, who also directed Alien and Blade Runner, added: 'He pulled the trigger and it goes 'Bang'. Idris thought he'd been shot and dropped to the sidewalk and said "I've been shot!"' Firearms expert Paul Biddiss, an advisor on weaponry for films and currently working with Scott, said: 'He is very hot on safety. 'What he was referring to by a solid barrel is a completely filled in barrel that no bullet would be able to pass through, so it was a completely deactivated impractical gun as far as firing anything was concerned. 'But he was still able to create a recoil effect for the film's purposes by using something used in films called a UTM round. which can be put in a weapon that has had the barrel completely filled, and it still causes a blowback. 'It is like a small silver case with compressed air that reacts. It can be used repeatedly for a recoil effect each time. 'It's quite often used in close up execution shots in films.'