I'm not sure what leads you to believe that "Running them at nearly 3,000 FPS from a 22" competition barrel" calls for you to comment in this manner. Are you suggesting that I'm not capable of working up an accurate load safely? And if so, what is your experience and training which calls for such a comment?
There can be slow or fast barrels, barrels which show pressure signs before we might expect them to. Chambers which are cut improperly, allowing for pressure signs to show up when maybe they aren't expected even by comparison to published data?
This is just a tiny bit of data which I gathered from several range sessions developing a load for PRS competitions. Yes, it's an AR10 of course. It's also a +2 barrel and gas tube with an adjustable gas block.
A gas gun cannot handle the pressure of a bolt gun, +2 tube and adj gas or not. The locking mechanism of the way the bolt works in the carrier with it's relationship to the barrel extension, and the simple design of the rifle's mechanics, dictate this.
You need to buy a better chrono. You are NOT shooting a 112 MB 3000fps out of a 22" AR10, unless your definition of "nearly" is 2850fps.
The 6GT barely shoots over 3k fps out of 26" bolt guns and 105gr bullets without ruining brass in more than 2 firings.
Go ahead, ask me about MY experience level.