Marine marksman sheds light on how gunmen from the 'hood unwittingly use a well-known aiming technique

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.

Instead, gangsters - albeit unkowingly - use another method to get what's called a 'flash sight picture' by quickly aiming down the side of the gun barrel without perfectly lining it up with the target. The 'flash sight picture' is a way to quickly get an aim that's good enough for combat but without worrying too much about being totally precise with your aim. Marines do it too, Mr Davis says, but they hold their guns the right way up.

In answer to a question on quora.com Mr Davis explains: 'The problem with tilt style shooting is that it is almost impossible to acquire a reliable sight alignment. The alignment in tilt style is achieved by making the weapon flat and aiming down the side. 'In theory this works, but in practice you can't accurately measure movement left or right and you have absolutely no way of knowing if the weapon is tilted down below your field of vision from the back of the weapon. 'This means that you never actually take the same shot twice since you are never actually aiming the same way.' This, Mr Davis adds, shows that there is in fact a rational method behind why gangsters aim their weapon side on. However, it's not a particularly good method - and they probably don't realise that there's method to it at all.

http://www.dailymail.co.uk/sciencetech/article-2212899/Marine-marksman-sheds-light-gunmen-hood-unwittingly-use-known-aiming-technique.html