In an AR-15, the gas block sits neatly underneath the handguard, positioned right above a strategically placed hole atop the barrel. Most AR-15 rifles have the 0.750" diameter gas port barrel.
Here's how it works: when you fire a round, a portion of the gas produced zips back through the gas tube and travels back into the chamber. This is a crucial part of the rifle's operation.
How to Pick the Right Gas Block Size for Your AR-15
When you're in the market for a new gas block for your firearm, it's crucial to match it to your barrel's diameter. Typically, you'll encounter gas block sizes denoted in inches, like the common 0.750". This measurement should correspond to the width of your barrel to ensure a proper fit.
If you have a barrel that's on the slimmer side, reminiscent of the vintage M16A1, you'll be looking for a 0.625" gas block. On the other hand, for those beefier, thick-barreled rifles, a 0.936" gas block is your go-to.
Gas Block Considerations
Adjustable Gas Blocks
Adjustable Gas Blocks allow you to tweak the amount of gas that cycles through your firearm, especially when you're using various types of ammunition especially when shooting suppressed. This flexibility can be a real game-changer in preserving the lifespan of your gun's components. It's like having a customizable setting for different shooting scenarios.
Low Profile Gas Blocks
Thee low profile gas blocks are very popular for AR15s with free float handguards. Because they fit snugly under those rails without any contact with the rail, and it provides a seamless integration that doesn't mess with your your firearm. It's all about maintaining that perfect balance between functionality and form.
Lightweight Gas Blocks
These are a top pick for competitive shooters. In shooting competitions, every ounce counts. Opting for a lighter gas block means your rifle won't be weighed down, giving you that slight edge in speed and maneuverability.