As you research AR-15 accessories and upgrades, you will come across two gas systems: direct impingement or piston. These two gas systems are how the AR-15 fire, return the bolt, strip an old cartridge off of the magazine, chamber a new round, and fire again. There are pros and cons to both systems, but a large majority of the AR rifle systems utilize the DI system.
There are specific reasons why you would utilize a piston gas system, but you can decide which system you want to use once you know a little bit more about each.
Piston vs. Direct Impingement (DI)
What’s The Difference Between DI and Piston?
A large majority of AR gas systems are direct impingement. Hot gas is directed from behind the bullet into the gas tube, where the gas is sent directly back to the chamber. This results in the bolt unlocking and moving backwards, the casing expelling, and then pushing a new cartridge into the chamber.
The piston works in a similar fashion, but it does not involve sending the hot gas back to the chamber. Instead, the hot gas is used to effect a piston that initiates the unlocking, expelling, and inserting a new cartridge.
Piston Pros and Cons
If you’re considering breaking the mold and going with a piston setup, here are some of the most common pros and cons to consider.
Cons:
- Costs more than a Direct Impingement System
- Places more weight in front
- Some parts are unique to the manufacturer
- Reduces accuracy
Pros:
- Gas is vented away, so the process is cleaner
- Said to be more reliable when encountering dust, water, etc.
Overall, a piston system will work just fine for your needs. If you’re shooting after being in water, dust, sand, or “rough” environments, you will want to consider a piston gas system a bit more than you would otherwise.
Gas Block
The gas block is what utilizes the hot gas from firing the rifle and returning the bolt. For some, the “front sight base” (FSB) combines the front sight and the gas block into one component. For others, they prefer to use a gas block so that they can implement a free-floating rail. You will find in the market low-profile gas blocks that better suit the customization of AR-15s.
What’s more, some of these blocks are adjustable, which means you can control the amount of gas used.
For most, the desire to install a rail on their rifle means they want to skip the FSB and go straight for a gas block. Also, consider the type of barrel you are using to decide on which gas system best fits your needs.
Rail Scales: High-Quality AR-15 Accessories
Now that you understand the difference between a DI and a piston gas system, you can make the best choice when upgrading your rifle. For the most part, you will want to go with a DI system, but the choice is ultimately yours. In the meantime, give the Rail Scales AR-15 accessories a look to find your next upgrade. Shop online now!