How to Install a Low Profile Gas Block On An AR-15

How to Install a Low Profile Gas Block on a AR 15
Alfred Mendoza

Gas blocks house the tube and fit at the top of the gas port in the barrel. It creates a secured seal over the gas port.

It drives the bolt back in a straight impingement system. Too much or too little gas leads to other concerns.

Here’s how to install a low-profile gas block on an AR-15 – on your own!

1. Clean Your Rifle & Prepare Your Tools

You have to ensure that the parts are clean on your rifle. For example, the barrel nut needs to be free from any carbon build-up as it may affect the size, especially important for competition shooters.

The gas block needs to be degreased. Ensure to degrease the gas block screws, allowing the thread locker to hold properly. 

When cleaning your AR-15, you shouldn’t use grease that has metallic additives. Instead, apply simple tetra gun grease to the receiver’s threads and barrel extension.

It may result in your set screw backing out. Also, remember to check out the respective state laws.

You do need several tools for your DIY gun building process:

  • Barrel dimpled for a gas block set screws
  • Barrel nut that secures the bolt carrier group
  • A proper torque wrench
  • Handguard nut
  • Breaker bar 
  • Roll pins
  • Gas block roll pin
  • Gas key
  • Gas tube roll pin
  • Gas tube alignment tool
  • Barrel nut wrench
  • Gunsmithing hammer
  • Allen keys
  • Roll pin punch

2. Insert the Gas Tube

It’s essential to make sure the tube opening faces down into the gas block, allowing it to line up with the porthole there. 

An adjustable gas block leaks more than a standard gas block, so keep that in mind before choosing an adjustable gas block.

3. Use a Roll Pin to Drive Through the Gas Block

When done with the tube insertion, you will utilize a small roll pin starter punch to drive the roll down the gas block. 

You have to switch to the roll pin directly and then drive it until it’s flush. Some are roughly sub flush on both sides.

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4. Slide the Gas Block Into the Rifle’s Barrel

As for the next step, you need to slide the gas block onto the barrel nut. You have to make sure that the gas tube goes over the nut and into the upper. 

After which, the gas block is properly lined up. At the top of the block and the tube, it needs to be at twelve o’clock, which matches the top of the upper. 

If things aren’t properly aligned, the gas system will run without gas, and your gun won’t be able to cycle correctly.

You can loosen the barrel nut by securing the barrel nut wrench below the barrel, and then you pull up from its left side. The front sight can be left alone.


5. Make Adjustments, Screw In Place & Tighten

Now, you need to screw it in place. To do this, you apply a small amount of the Red Loctite (271) and put the screw in with your set screws.

You need to screw it in place to achieve a tight fit. Also, you need to recheck the alignment of the gas block, so you can make the necessary adjustments. You have to align the roll pin hole and the gas tube hole.

After that, you need to redo the steps with the second crew, including rechecking the alignment to properly tighten. Also, ensure that the lower receiver and upper receiver are in place.

If your AR-15 handguard doesn’t provide torque specs, you need to tighten the barrel to 40 to 50 ft-lbs to have it properly installed. Most barrels come with the commercialized torque specification.

Our Final Thoughts

It’s pretty easy to set-up low profile gas blocks, and it’s best to choose the standard than the adjustable gas blocks as it leaks more. 

Keep in mind that there are different attachment methods and state and federal laws (1). 

You need to do your research or contact the local ATF representative for your completed firearm.



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