How to adjust gas block?

Effective way is to use an A2 tool.
1. Remove the charging handle and bolt carrier group from your upper receiver.
2. Unscrew the gas tube from the gas block. Once the gas tube is removed, you will be able to see the inner workings of the gas block.
3. Use the A2 tool to adjust the set screws on either side of the gas block until they are flush with the sides of the gas block. Be sure not to over-tighten these set screws, as this can damage your gas block.
4. Screw the gas tube back into place and reassemble your upper receiver.

We also recommend watching this video

1. Make sure that the area around the muzzle device is clear of any tools or other objects that could cause an obstruction.
2. If you have a set screw type adjustment, locate the set screws on the side or top of the gas block and use an appropriate size hex key to loosen or tighten as needed. Be careful not to over-tighten as this could damage the set screws.
3. If you have an adjustment nut, locate the nut on the side or top of the gas block and use an appropriate size wrench to loosen or tighten as needed. Again, be careful not to over-tighten as this could damage the gas block.
4. Once you have made your adjustments reassemble your firearm and test the fire to ensure that the gas flow is correct.

For most gas blocks, there will be two screws that control the gas flow.
Loosen these screws slightly and then cycle the action several times to bleed off any excess pressure.
Next, gently turn one of the screws clockwise or counterclockwise until you achieve the desired level of function.
Remember to test-fire the weapon before making any final adjustments!

For adjustable gas blocks, there is usually an adjusting knob or set screw that can be tweaked to increase or decrease the volume of gas that flows through the block. For fixed gas blocks, you will need to remove the entire gas block and replace it with a new one that is properly sized for your needs.
Be sure to take note of how your current gas system is configured and which type of parts you will need before making any adjustments. Don’t hesitate to consult a professional if you are unsure about how to proceed. With a little bit of care and attention, you should be able to get your gas block tuned to perfection in no time.