Firearm Myths - 5 (Fun with Lasers)

We haven't covered any myths for a while, the last article was over 2 years ago. In today's post, we will cover a scene that often shows up in movies and TV. Check out the two screen captures from the popular TV show Sherlock, starring Benedict Cumberbatch as Sherlock Holmes and Martin Freeman as Dr. John Watson.

Click on the images to enlarge.

In the scene, Sherlock Holmes has just arranged a meeting with his arch enemy, Moriarty, and plans to use his pistol on him. Unfortunately for Sherlock Holmes, Moriarty has planned for this and has positioned snipers in the buildings around, and they are pointing their red laser sights at Holmes and Watson.

Now, we look at another scene from a different movie, Captain America: The Winter Soldier.

Scene from Captain America: The Winter Soldier

Here we see that agent Jasper Sitwell is taking a phone call that informs him that he has just been targeted by a sniper and he looks down to see a red dot visible on his tie.

So, do snipers actually use red lasers on their sights? Let's see what the real story is.

First, red lasers are not really very visible in bright daylight, a fact we covered a while ago. Green lasers are a bit more visible, but use up a lot more battery power. So, the scene from Captain America, where a bright red laser dot shows clearly in broad daylight, is a bit of Hollywood movie magic and is not possible in real life.

Now let's look at another thing about laser sights. They are useful to acquire targets quickly at short range, because the user can see exactly where the weapon is pointing at, without peering through the weapon's other sights, especially in low light conditions.

However, laser sights are not useful for long range snipers, due to a few reasons:

1. The primary goal of a sniper is to stay hidden. If a real sniper used a laser like the types shown in the images above, everyone would know where the sniper is, because they can just follow the laser beam back to the source.
2. The target will also know that he or she is being targeted and can possibly attempt to take evasive action.
3. Laser light travels in a straight line, but bullets don't. A laser sight completely ignores the effects of gravity, wind, air density etc. This is why rifle sights have adjustments for elevation and windage. 

For these reasons, the scenes with the snipers are highly questionable. They look pretty good on TV though.

Sights: Laser Sight

We've spent the last few posts discussing iron sights and telescopic sights. In this post, we will study a new type of sight that is mainly seen with handguns and rifles, the laser sight.

A laser is merely a light source which has the property that the light emitted is focussed as a narrow beam with very little divergence. This is unlike a regular light bulb that emits light in many directions in a variety of frequencies. Due to the property of low divergence of the beam, lasers can be used to indicate the aimed point on a target.

The original laser devices were extremely large and bulky, but due to advancement of semiconductor technology, they can be made much smaller these days. The typical laser sight today is small enough to be mounted to the underside or top of a pistol.

The laser sight is attached so that it is parallel to the barrel. Since a laser beam does not diverge much, the user can move the barrel until the light spot from the laser hits the desired target. The spot indicates the area where the barrel is pointing to. It must be remembered though, that the light travels in a straight line, but real bullets travel in an arc, due to forces of gravity, wind etc. The user may therefore need to allow for windage and elevation depending on the distance between the weapon and the target.

Most laser sights utilize red laser diodes. In the late 1990s, green laser diodes were invented, but it wasn't until 2007 that the first mass produced green laser sight was invented. Green laser sights are a bit more expensive than red laser sights and consume more battery power. However, green laser light is much more visible to human eyes than red laser light, especially in bright daylight conditions.

The two pictures above show a red laser and a green laser during day time and night time. In the bright day time shot, the red laser dot is barely visible in the picture, whereas the green dot is easily seen. The green dot is also seen much more clearly at night time, where the entire beam is clearly visible, not just the dot. With red lasers, only the dot is visible normally and the beam is usually only discernible when the surroundings have smoke or dust. This makes weapons using green lasers much more easier to aim than red laser sights.

One of the disadvantages of red and green laser systems is that the target (and other people surrounding the target) can also see the dot and be aware that he or she is being targeted. Also, the visible beam gives away the position of the person pointing the weapon. Therefore, some systems use an infrared laser that is only visible to people wearing night vision devices. Unless the target is also wearing a night vision device, he or she is not aware of being targeted and doesn't know where the person aiming the weapon is either.

Laser sights allow the user to quickly acquire a target. With other types of sights, the user needs to concentrate on pointing the sights to the target and therefore loses focus of things that are surrounding the target. Laser sights allow the user to not lose details of the target's surroundings. It also allows one to aim the weapon without physically staring down the barrel, which allows for greater concealment.

On the other hand, laser sights need batteries and there is the chance of the batteries running out when they are needed. Red laser beams are hard to see in daylight or in clean surroundings. Green lasers are more visible in bright or clear conditions, but they chew through batteries much more quickly than red lasers and are also more expensive than red lasers. Laser sights also alter the balance of the weapon somewhat and rough usage can change the spot where the laser is pointing, which means it no longer points to where the barrel is pointing.