It’s an iconic image immortalised in dozens of Hollywood gangster films: the gangster aiming down the side of his pistol before pumping a volley of bullets into his victim. But with most people knowing that the aiming sights are found on the top of a gun barrel, it’s also a counter-intuitive way to accurately fire a weapon.
So why is it that gangsters are always shown using their guns in this way? According to Jon Davis, a former marksmanship instructor with the U.S. Marine Corp, there is a good reason, at least in theory.
As a specialist in pistol marksmanship and a veteran of the war in Iraq, Mr Davis has fired these kinds of weapons thousands of times.
He explains that when aiming a handgun in the conventional, barrel-up manner the rear sites must line up with the front sight in the horizontal and vertical planes to make sure the bullet travels a straight line.
This important technique, known as ‘building the castle’ since the gunman has to line up the three ‘turrets’ into an even position, ensures that the barrel of the gun is aligned perfectly along the trajectory he wants the bullet to travel.
The problem with ‘building the castle’ each time you want to fire your gun is that it takes time. Time you might not have in a combat situation or alternatively when you want to quickly execute your victim and make a fast getaway.