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.
We 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, we wanted GPT to be anything but, as we 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 power 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 Forward Controls Design & Modern Armory. Forward Controls Design's version can be found here: https://www.forwardcontrolsdesign.com/GPT-Gas-tube-Pin-Tool_p_218.html
Compatible with most gas blocks including Modern Armory, FCD GBF (Gas Block, Forward Controls), BCM, Rainier, VLTOR, Knight's Armament, 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, BA Hanson, Luth AR, and DPMS, and adjustable gas blocks.