It has long been our belief that the ideal AR-15 should have 2 simple mods – normal and suppressed. This K.I.S.S. concept optimization mindset stems from Griffin’s baked-in military background, where simplicity is king. A simpler setup is less likely to fail, and allows less ways for the operator to get confused about a setting, or how something functions.
The Griffin Adjustable Gas Block has been prototyped, modified, and fully developed with this ethos strongly in mind, and builds off two patents acquired by Griffin from MicroMoa LLC – the original manufacturers of the “Govnah Gas Block”. Further design changes and improvements were made to optimize the product for Griffin’s manufacturing processes, and to bring machine time and subsequently cost down for the end user.
The Griffin Adjustable AR-15 Gas Block provides normal and suppressed operation via rotationally sliding a regulator plate from the Normal position to the Suppressed position. This regulator plate is detented via a 718 inconel spring and ceramic ball bearing ensuring material strength under extreme operating temperatures. There are two 180° opposed sides of the regulator plate, each affording a normal and suppressed setting (Refer to the spreadsheet covering regulator hole sizes). One side of the block is identifiable by two grooves cut on the side of the selector cutout. This allows a shooter to find the side of the disk that works best for an application, and if that is the grooved side, a paint pen can be used to make a vertical mark on the right side of the rail, allowing the end user to know the grooved side is on the right (laser marked side of the block) when that build is used. Once this initial setup has been determined, a one-click operation configures the rifle from normal to suppressed modes of operation.
What Sets this Apart from Other Options?
Many adjustable gas blocks on the market today are designed as a one-size-fits-all solution, with a variable range of settings that can be selected (Think Riflespeed, one of if not the most common adjustable gas blocks out there). It is up to the user to determine which setting is right for their setup, and then record or remember that position or numerical setting to switch between modes.
The Griffin Adjustable Gas Block takes a fundamentally different route. By only offering two positions (effectively three actually, but we’ll talk about that later), there is no remembering of anything, and checking the status of the firearm is as simple as peering through the rail and seeing if the slider notch is positioned forward, or backward. “Tuning” the block to the host firearm is not done via changing of the settings, but rather by changing the Regulator Plate that is easily installable and removable.
Griffin offers 10 different regulator plates that are pre-built to work with most setups right out of the box. Choosing the right plate when you purchase is based on the gas system length of the intended firearm it will be installed to, and the type of suppressor being used – conventional or low backpressure (high flow). Based on those two criteria, you end up with 10 unique plates optimized for the different setups (see list below).
- Rifle Length – Conventional Suppressor
- Rifle Length – LBP Suppressor
- Mid Length – Conventional Suppressor
- Mid Length – LBP Suppressor
- Carbine Length – Conventional Suppressor
- Carbine Length – LBP Suppressor
- Pistol Length – Conventional Suppressor
- Pistol Length – LBP Suppressor
- Pistol Length .300BLK – Conventional Suppressor
- Pistol Length .300BLK – LBP Suppressor
Griffin also sells 2 plates that are pre-drilled, but not sized, allowing a customizable set of port sizes for the avid gunsmith who wants and knows specifically what port size is required to optimize their specific platform. (The pre-drilled plates are definitely the way to go unless you have an in-depth understanding of port sizes and AR-15 gassing systems)
Once you’ve chosen the correct plate for your setup and installed it to your rifle (utilizing a straight gas tube of course), you have a decision to make. Remember earlier we mentioned that there were effectively 3 positions? Looking at a plate, you’ll notice there are four holes drilled rather than just two as you might expect. The two larger holes are simply pass-throughs, that allow your barrel’s port size to operate as intended when unsuppressed. The two smaller holes are the suppressed holes, and differ in size by .004″ for conventional plates and .008″ for LBP plates between the two holes. This allows the user to choose between those two port sizes based on their setup for the one that performs better. This operation is achieved by rotating the regulator plate a full 180° to the other side, thus utilizing the other port size for suppressed.
No matter which side of the plate you end up, you will be able to easily flip between that setting and the unsuppressed setting with a simple flick of the plate through the rail using a bullet tip. Once you’ve determined the correct side of the plate to be on, you can leave it in that orientation and flip back and forth. So while this is a two-position setup, you technically get two variations for the suppressed port size. Pretty cool right?
The .008″ spacing on LBP plates was decided on due to the wide range in backpressure performance present in the LBP suppressor scene.
Who is this Product Right For?
We feel this product is ideally used on a standard setup, something that you keep set up the way it is with the same suppressor whenever you are using it. If you are a tuner guy who is always changing out parts, barrels, and suppressors, you might be better off getting one of the one-size-fits-all solutions available. Alternatively, you could pick up a range of regulator plates, which we sell separately as well as in a kit with the actual block, and change out plates as needed – a very simple process.
This gas block is perfect for anyone looking for a simple, two position setup, who doesn’t want to rely on memory of positions across a wide range of available options. Looking through the rail, the user can easily determine what setting the rifle is in by looking at the notch in the plate, and referencing the N (normal) and S (suppressed) marks lasered into the gas block itself. If those marks ever become too fouled to read, just remember, Notch Back = Normal and Notch Forward = Suppressed. It’s as simple as that.
The Griffin Adjustable Gas Block is available sold on its own with an included plate of the user’s choice, or as a $45 add-on to any of our complete rifle or upper builds!
About the Author
Benjamin Kubek is the Marketing Director at Griffin Armament and is an avid fisher, hunter, and suppressor nut.