I just received Super Duty 16" upper that came with Huxwrks md. I tried torch, I tried boiling water for 15 minutes. The damn device stays there. I have a vise with Geissele reaction rod. However, it feels like the barrel/upper are twisting when I am applying torque to the muzzle device.
Any suggestions? What does Geissele use ?

Hello,

The HUXWRX flash hider is not Rocksett like previous muzzle devices. It is simply not needed. We use HUXWRX's installation method of Red Loctite and torquing to spec. Heat and a Super Reaction Rod to support the indexing pin are always recommended and should be sufficient to remove your muzzle device.

We always recommend the aid of a certified Gunsmith to avoid any issues or damage to your upper receiver. You can also reach out to our CS team on Geissele.com and we are happy to continue to help.