Fixed A2 Front Sight Post with Integrated Gas Block

Fixed A2 Front Sight Post with Integrated Gas Block

Gas blocks serve an important role in the function of your AR-15.

Whether rail height, low profile, or part of a fixed A2 front sight post, the gas block holds the gas tube in place, which is key to the cycling of your AR.

Gas blocks are precisely positioned over the gas port in the barrel of the AR. When a round is fired, the bullet travels down the barrel, propelled by gas. Once the bullet passes the gas port in the barrel (a tiny hole in one side of the barrel), the gas is forced through the gas port contained by the gas block, through the gas tube, and back into the upper receiver to cycle the next round in your magazine.

Rail Height Gas Block

Rail Height Gas Block

Low Profile Gas Block

Low Profile Gas Block

As it applies to direct impingement style AR-15s: Stainless-AR-15-gas_tube-2

When a round is fired, the bullet travels down the barrel, propelled by gas. Once the bullet passes the gas port in the barrel (a tiny hole in one side of the barrel), the gas is forced through the gas port contained by the gas block, through the gas tube, and back into the upper receiver to cycle the next round in your magazine.

There are typically 4 different lengths of gas tube: pistol, carbine, mid-length, and rifle-length.

While most calibers prefer a longer gas system to cycle smoother, certain calibers like the 300 Blackout actually prefer a shorter gas system for proper cycling.