Forward Controls Design GPT – Gas Tube Pin Tool

Original price was: $35.00.Current price is: $33.25.

In stock

SKU: GPT UPC: 686162347865

Product Description

GPT (Gas tube Pin Tool) is a jig tailor-made for installing and removing the gas tube roll pin on an AR15/M16 low-profile gas block. Machined in 6061 aluminum and Type III hard coat anodized, GPT makes installing the gas tube pin on a low profile gas block painless. GPT is designed to be stable and surefooted, but it is no larger than it has to be, in order to retain a reasonable small footprint on the crowded workbench.

Most low-profile gas blocks don’t have flats and are hard to hold steady without requiring 3 hands to install the diminutive gas tube roll pin. GPT enables the user to install the gas tube roll pin, and remove it as well with ease.

FCD made its base thick and wide for stability, its base is rebated to allow the user to clamp it down in a vise. Thoughtful touches can be found on the GPT, from the scalloped finger access recess to the soft, rounded corners and edges, even its green color has a purpose. Most gas blocks are black, FCD wanted GPT to be anything but, as they found it more difficult to work on a black gas block that sits in a black jig. GPT’s green color provides a pleasant contrast and makes the black gas block stand out.

With a small Neodymium magnet placed on the gas block, it’s powerful enough to stand the gas tube roll pin can upright, perpendicular to the gas tube, above the gas tube pin. With one hand holding the gas block steady in the GPT, one can start tapping on the gas tube roll pin to get it started.

GPT is a collaboration between Modern Armory and Forward Controls Design. Modern Armory’s version can be found here

Compatible with most gas blocks including Modern Armory, our GBF (Gas Block, Forward Controls), BCM, Rainier, VLTOR, Knight’s Armament, Badger Ordnance, Daniel Defense, SLR, or other low profile gas blocks based on the original Crane design.


  • Please measure your low-profile gas block dimensions, as some are longer than others. GPT is made for Crane Mk12 pattern low profile gas blocks, the length of which is 1″. GPT can be modified to accommodate longer gas blocks.
  • MAX gas block length: 1.00
  • MAX gas block height: 1.35

Known incompatible low profile gas blocks:

Aero, Luth-AR, and DPMS, and adjustable gas blocks.




Technical Information

Color / Pattern
Finish Anodized
Material Aluminum

Catalog Location

California Prop 65 Warning

WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information visit

Customer Reviews

Based on 3 reviews
Adam K.

It worked

ken a.
Got it to work, but not perfect

I found one of the most difficult things to do when building your upper is pinning the gas tube to the gas block. Because of the shape of the gas block it is really difficult (nearly impossible) to get it in a stable position to give yourself a straight shot at pounding the pin into the gas block. I tried it with a regular bench block, but couldn't do it. So after some online research this one seemed this one was pretty good, so I ordered one. After receiving it I found it very nice and well made. And it will work well with most standard gas blocks. But I have a Superlative Arms adjustable gas block, and it has an extra little doo-hickey thingy in the front. So it works fine facing one way, but it doesn't sit right facing the other way. And I needed it both ways, to pound one pin out, and then pound a new pin in. Also there is a hole for the pin fall through facing one way, but if you want to pound it out the other way, you would have a harder time because there isn't a hole on the other side. I was able to make it work, but it would have been easier if it was a little roomier in case you have extra doo-hickey thingys on your gas block. Not perfect, but way better than just a standard bench block.
Ok, I just looked at the description, and it lists the gas blocks that won't work, and it mentions that it won't work for adjustable gas blocks.
I got it to work, but it wasn't ideal. It would be nice if they made it more universal, with enough room to work for adjustable gas blocks too.

Gas block jig

This works great. Should last a lifetime and beyond.