They just dropped this today. Pretty cool. Specifically the part where you can swap out manifolds and drill your own ports in the manifold plates. I've been drilling and tapping the gas ports in fixed gas blocks and using the grub screws as manifolds, by drilling them out with fine #48 or #52 bits. This allows for two settings and offers manifolds with pre-drilled 0.034" holes for you to open up. Complete customization for a dual rifle setting
Griffin two position adjustable gas block
- Thread starter JR1200W3
- Start date
Interesting concept, but I wonder how good of a seal you can get between the adjustment manifold and the body of the gas block. Someone used to make a similar design, but the manifold slid back and forth perpendicular to the bore axis. It was a leaker.
I sat through most of this video before I had to cook dinner, but I like what I see. I’m probably going to wait in some reviews but this might be purchased for a 12.5 SBR I’m piecing together.
I just put together a 12.5" pistol. The barrel came with a .080" gas port on a hybrid length gas. It was violent, hard recoiling, and loud as shit with a suppressor. I drilled a set screw out to .070" and then again to .067" and installed it in the gas block. It runs well suppressed with a 67 thou port.
Here is my variation of that mod. Most set-screw gas blocks use 10-32 set-screws. The drill size for a 10-32 tap is a #21, or 0.159", and some manufacturers drill the gas block passage connecting the gas port to the gas tube at the same time and with the same drill as when they do the set-screw hole. If the gas block is like that, you only need to tap the gas passage, use a ported 10-32 screw, and then you can still use the rear set-screw. Plug or bottom taps work well, as you can tap to a depth where the ported set-screw bottoms out just short of the gas tube bore. If the gas passage is smaller than 0.159", like 0.125" which is also common, you can open the passage up with a #21 through the set-screw hole, then continue.
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