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How to Replace an AR-15 Gas Block

How to Replace an AR-15 Gas Block


How to Replace an AR-15 Gas Block
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I wanted to add a free float rail to my AR-15, but my A2 Style front sight was in the way.  I had to remove it and replace it with a a low profile AR-15 gas block.

This was not complicated, but it did take some effort.  Proper tools of good quality make this process much easier.

The recommended tools are:

  • Cupped Punch
  • Good Punch set
  • Hammer
  • AR-15 Gunsmiths block
  • Vise
  • AR-15 Upper Receiver block
  • AR-15 Barrel Wrench

Here is the basic process.

  • Remove hand-guards and upper receiver
  • Unscrew the flash hider and crush washer if present
  • Remove the tapered pins holding the front sight/gas block
  • Remove the pin holding the gas tube to the front sight/gas block
  • Pull gas block off end of the barrel – a block of wood may help is the gun suggest the block move.
  • Put the gas tube into the gas block, align it so the large roll pin hole lines up with the roll pin hole in the block.  Also you must make sure that the gas hole in the tube lines up with the gas hole in the block.
  • Slide the new gas block onto the barrel, be sure to line up the large gas hole in the block with the smaller gas hole in the barrel.  If the holes do not line up the gun will not work as a semi-auto
  • Tighten the set screws to tighten the gas block into the barrel

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