Wednesday, March 4, 2015

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.


  1. Another funny thing is that Moriarty says the pistol is a Browning Hi-Power, while you can clearly see it's actually a Sig P226. I know it's just a tv show, but is has bothered me anyway.

    1. Hi powers were the standard issue sidearm for the British army at the time, he probably assumed that's what John stole when he left, rather than the rarer SIG which was only used in small numbers as a stop gap measure.

  2. Actually I work with high precision lasers for a living and they actually don't travel in a straight line as much as you might think. Once you go beyond 100 ft(which I'd hope any competent sniper would be much further), humidity and wind both come into play. Humidity is obvious because of light refraction, but wind actually affects it over long distances because of possible temperature/climate fluctuations that can also refract the light. Overall, lasers and long distances make for and erratic beam