Nice link!Bang for the buck this guy sells great barrels, bolts, and other parts. He's an old time wild cat builder/designer. Most of his barrels are Melonite/Nitride hardened inside and out. He designed a much better bolt for the grendel and can help you scratch the itch
I am in no way affiliated with his company beyond having bought more than 20 barrels from him and a large stash of bolts.
https://ar15performance.com/__valkyrie__grendel___wildcats