I had previously gone down the route of the Heavy Buffer (10 oz buffer) and Wolff XP spring to try and alleviate the excessive recoil from being over gassed. They helped somewhat, but the result was still not as good as with an adjustable gas block on an AR-10 platform.
There had been one mention in this thread of the Black River Tactical "EZTune" gas tube, so I decide to give that a try (I have no affiliation with them, and was not familiar with them until reading the post). You tell them a bunch of variables and they come up with a recommendation or a custom tube: the barrel length (20"). caliber (.308), buffer (stock H3), spring (stock mil-spec), BCG (stock LMT), and suppressor (Gemtech), and mixed use or suppressor only use.
Looking at the their drop down menu, gas port inlet on the gas tube would range from 0.081-0.095 for 20"/.308 depending on the factors.
Gas tube came shipped in a cardboard tube with an included roll pin. Gas tube had the normal/large inlet on one side, and a smaller inlet 180 degrees opposite that. Installed it small inlet down, so that restricts the gas coming off of the gas block, and the normal inlet is doing nothing, as it is being blocked by the top part of the gas block.
Mine tube was "tuned" for suppressed use only. Cycled fine with M80 ball and M118 clone loads with the can installed. With the can removed, the spent rounds would eject, but the bolt would not lock back on an empty mag. Seems like they have it figured out! In the end, I think recoil and vibration is much less that with the 10oz heavy buffer slamming around and excessive gas.
So outside of going to an adjustable gas block, restricting the gas entry via the smaller port on the gas tube seems like the best solution. Instead of buying a second one from them for a 16" barrel, I may just buy a few gas tubes and a handful of numbered drill bits and experiment in making my own custom gas tube. YMMV.
There had been one mention in this thread of the Black River Tactical "EZTune" gas tube, so I decide to give that a try (I have no affiliation with them, and was not familiar with them until reading the post). You tell them a bunch of variables and they come up with a recommendation or a custom tube: the barrel length (20"). caliber (.308), buffer (stock H3), spring (stock mil-spec), BCG (stock LMT), and suppressor (Gemtech), and mixed use or suppressor only use.
Looking at the their drop down menu, gas port inlet on the gas tube would range from 0.081-0.095 for 20"/.308 depending on the factors.
Gas tube came shipped in a cardboard tube with an included roll pin. Gas tube had the normal/large inlet on one side, and a smaller inlet 180 degrees opposite that. Installed it small inlet down, so that restricts the gas coming off of the gas block, and the normal inlet is doing nothing, as it is being blocked by the top part of the gas block.
Mine tube was "tuned" for suppressed use only. Cycled fine with M80 ball and M118 clone loads with the can installed. With the can removed, the spent rounds would eject, but the bolt would not lock back on an empty mag. Seems like they have it figured out! In the end, I think recoil and vibration is much less that with the 10oz heavy buffer slamming around and excessive gas.
So outside of going to an adjustable gas block, restricting the gas entry via the smaller port on the gas tube seems like the best solution. Instead of buying a second one from them for a 16" barrel, I may just buy a few gas tubes and a handful of numbered drill bits and experiment in making my own custom gas tube. YMMV.
