How to Install an Adjustable Gas Block on AR-10 or AR-15 (SLR Rifleworks)


As mentioned in a previous article, Diagnosing a Failure to Feed *Video* AR-15 or AR-10, I had some failure to feed issues due to a part failure.  You can see how it was diagnosed, and narrowed down in the article:

For this article, we are going to show how I installed an adjustable gas block.  Then a short review, along with the pros and cons of this particular product.

The tools you need:

  1. Punches: I use regular flat punches, roll pin starter punches, and roll pin punches, but a regular set of punches will work just fine (that’s all I used for years);
  2. Gas Block:  I went with the SLR Rifleworks adjustable gas block (.936″ ID) to match the mid-weight Criterion barrel manufactured for Fulton Armory and chambered in .308 Winchester;
  3. Allen Wrenches;
  4. Time & Patience.

Remove the old gas block:




As you can see from the pictures, the old gas block was leaking.  That’s not gonna cut it, so it’s getting removed, and replace with an adjustable gas block from SLR Rifleworks.  That way if Mr. Man ever wants to run run this rifle suppressed, he’ll be set up.

1. Remove the handguard to get to the gas block.




2. Unscrew hex screws that secure the gas block to the barrel, and remove the old gas block.


Remove the old gas block. Dump it like Bruce Jenner did his Y chromosome!

3. Drive out the roll pin holding the gas tube in place.

4.  Inspect the used gas block.  When in doubt, simply replace it (I reused on this one because it isn’t very old).

5. Insert the gas tube into the new gas block, making sure to align the gas ports, as well as the roll pin hole.

Adjustable Gas Block

Gas tube inserted, gas port aligned, and roll pin hole properly aligned.

6. Using a roll pin starter punch (regular punch will work, but you will curse more), get the roll pin started.




7. Finish driving the roll pin through with a roll pin punch (or regular punch if that’s all you have).




8. Reinstall the SLR Rifleworks adjustable gas block and gas tube on the rifle, being careful to properly align the gas port on the barrel with the gas port on the inside of the gas block.

9. Tighten down the Allen Screws on the gas block being careful to keep everything aligned.  Get them snug, but don’t over tighten them.

Install SLR Rifleworks

Tighten down the Allen Screw, and you are GTG

10. Reinstall everything that you removed by doing the dyslexic version of what you preformed above.

Install Adjustable Gas Block

Pretty cool looking

SLR Adjustable Gas Block

The SLR Rifleworks Adjustable gas block can be adjusted with the use of an Allen Key without the removal of the handguard.  It fit well beneath this Midwest Industries Handrail.


The quality of the SLR Rifleworks gas block is so far beyond that of a run-of-the-mill standard AR-15 or AR-10 gas block that it almost isn’t fair to compare the two.

The Pros for the SLR Rifleworks Adjustable Gas Block as I see it are as follows:

  • It is a solid piece of 4140 steel, with a Melonite finish;
  • CNC and/or mill work are impeccable;
  • It looks like it is from the Kingdom of Badassdome;
  • It can be easily disassembled and cleaned if necessary;
  • The metering screw (the screw used to adjust the gas flow) is solid, and appears to also be made from 4041 steel…nothing flimsy here;
  • The way that the gas block is designed allows for adjustments in 15 “clicks,” so you can easily return to exactly the same gas setting by counting click adjustments (similar to a scope) for a variety of ammunition, and/or suppressed vs. unsuppressed situations.
  • This guarantees that regardless of ammo type or if you are using a can that you can adjust the rifle to the ammo, giving the user much more versatility when compared to a stagnant gas block.

The Cons for the SLR Rifleworks Adjustable Gas Block as I see it are as follows:

  • The gas block is on the heavy side when compared to other low profile gas blocks.  This is due to the increase in solid construction from reliable materials, and the difference in weight is negligible when compared to a standard gas block, so this negative isn’t all that negative.
  • I would like to see the Allen Key size for the adjustment/metering screw slightly larger.
  • I would like to see the ability to adjust the gas block in the field, by hand if possible because I don’t carry around a long handled Allen Wrench with me all the time.  Again, this is a very small detail that is not out weighed by the pros of this device.  Note that this rifle actually has a recess in the stock that I will be storing the adjustment wrench that came with the gas block for just such an occasion.

Although I can be bought, I have not been supplied with any products, nor have I been paid anything by SLR Rifleworks. This is my honest assessment of a product that I’ve used, and figured I’d pass it along to you numbskulls.

Categories: diy, hunting, reloading, Shooting

Tags: , , , , , , , , , , , , , , , , ,

7 replies

  1. A very well written (and illustrated) instructional feature! I’m saving this for the day I may have to undertake the procedure. Thanks for the great post!


  2. Helped me get to the bottom of my issue. RCA titanium BCG, KYNTEC hydrauic buffern (3.25″),
    Sprinco Orange buffer spring, and a Superlative arms adjustable gas block on a Aero M5 buoldKit using an 18″ BSF c/f bbl. I would have an occasional FTF andit was orevalent only with PMC 7.62 ammo. I opened up the gas a couple of clicks and it is a beast, I came in at 7lb 1.6oz and am very pleased with the build. Not the lightest .308 out there especially with the prevalence of the scaled downvariants but for an Aero Prec M5 and 18″ barrel I am pleased. I topped it with a 4-12 Leupold and after sighting in this thing is a surgical instrument.


  3. What thickness is the board you used to support the gas block while driving the gas tube pin?



  1. Diagnosing a Failure to Feed *Video* AR-15 or AR-10 – Greatoutdoordinary

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: