While not always the first part of a gun that the owner focuses on, the AR 15 gas block plays a very important role in the overall performance of the weapon. As a general guideline, the gas block is used to divert some of the gases that are a product of the firing of the weapon.
There is propellant on the bullet, which creates a gas when fired. This gas is diverted or shunted up and through the gas block and into the gas tube. From the gas tube the gas travels through the key and actually helps to push the bolt backwards. This action will assist in ejecting the spent casing out of the chamber.
At virtually the same time the bolt hits the buffer spring and it is driven forward forcibly, which in turn pulls a new round into the chamber, so the gun is immediately ready to fire again.
General Considerations
The AR 15 gas block is typically not adjustable, so there is very little in the way of maintenance for this component. There is no need to even clean the system as the gas is propelled with enough force through the block and the tube to keep the interior clean.
Additionally, the composition of the gas going through the block and the tube is not going to result in any debris or material collecting even if you are an avid shooter. Typically, the only reason a gun owner will change the gas block is for aesthetic reasons or to get rid of the standard fixed front sight and go with more streamlined sights or perhaps a scope.
Common Designs
There are several different types of gas blocks for an AR 15 made by different third-party manufacturers. These can be used to customize your gun to give it a unique look as well as to provide the right profile for the scope or sights you wish to use.
Low profile and adjustable profile gas blocks are very popular and they are a customization that is easy to complete on your own. These blocks are typically made of high strength steel with a specialized finish to make the component resistant to water, abrasion and general wear and tear.
There are different possible configurations with any of the third-party manufactured AR 15 gas block models, so just be sure to understand the differences and make sure this will work for your sights and scope.
