Here is a thought. Go to NAPA and find a freeze plug the right size. Drill 2 holes. 1 for the barrel and 1 for the gas tube. Flat black BBQ grill paint. Done.
Mine was drilled out to 5/64. I don't have a numbered drill bit set. Ran another 50 rounds through it today. 1 failure to extract. My barrel is marked 7.62x51 not 308. Not sure if that makes a difference. Still getting good groups.
The big bore AR's are not like the smaller calibers. We ask for information to try and help you with your problem. These guns are not "milspec". Different manufacturers come up with their own version of what MIGHT work. No need to leave but we can't help you if you don't give us the information we ask for.
You ask us for help with a problem. We ask you for some pictures and measurements. Now you tell us you have solved the problem by talking to people who sell poop not people who build,fix,and shoot these guns.
GOOD LUCK.
It may not be overgased it may be under recoiled. What is the inside depth of the buffer tube? How long is the buffer? What does the buffer weigh? Where does the gas tube end in the upper receiver?
I remember that thread. Had more to do with how they measured OAL. The main question was about forward vertical grips. And having to be over 26.5" to have one or it turned the pistol into an AOW.