This article is about Muzzle devices: Flash Hiders, Compensators and muzzle breaks. The industry uses these terms loosely and interchangeably. This is incorrect. After reading this article you will have a firm understanding about which is which and when to use what. They all have different purposes and selecting the correct device is essential in making your AR cycle like a well-tuned engine.
So, what is a flash hider? It is exactly as the term describes: hiding a flash. When and why would you want one of these? I think it’s obvious if you are in the military and engaged in combat at night but a civilian that is hunting may not want to diminish his night vision by looking at a bright flash and then waiting for his eyes to adjust again. Simple and straight forward, there should be no confusion here.
Flash Hiders exhibit no compensating or breaking effects. If you look into your 5.56 flash hider you will notice that the hole is much larger than the projectile and therefore has no effect on the gas system. By design a hider does exactly what it is supposed too with no other effects about the firearm’s system.
Moving on, we now enter into an area of muzzle devices that is a little more complicated and is a topic of much confusion, even among rifle enthusiast and industry leaders. True there are varying styles and designs that exhibit properties of both breaks and compensators but, by definition we are trying to accomplish to very different objectives with the use of each of these tools.
By definition a compensator is a muzzle device that should counter act any vertical movement in the barrel after firing. Called climbing, this is an effect that is caused during the recoil of the gun. A compensator attempts to adjust this action by directing the gas flow at the muzzle device upwards therefore creating an opposite force with gas pressure.
Observing the previous picture we see that escaping gasses can create a force in any direction we choose to vent them. So could we in theory use these gasses to reduce felt recoil? This is what a muzzle brake is designed to do.
Let‘s look at another diagram:
If the blue arrows represent trailing gasses and as those gasses are given room to expand they begin to propagate outwards. Since there is a wall inside a muzzle break to catch the trailing expanding gas it creates a force on this wall opposite the direction of the recoil of the gun just milliseconds after the bullet leaves the muzzle. This opposing force reduces felt recoil.
Now that you understand the basics it’s time for you to decide what muzzle device best fits you and your AR 15. Knowing the ins and outs of your rifle will help you make the right choice. Remember not all devices are the same and most exhibit more than one property in various combinations.