One of the biggest reasons I sold my POF. Proprietary parts from POF that they will sell you, however they have a proprietary barrel nut in which they won't sell the wrench for you have to send it back to them to get the barrel taken off. I simply wanted to take my barrel off and cut it down to 16" and rethread it for my suppressor. They wouldn't sell me the wrench so I sold their gun and bought one with common parts that I can take apart myself.
Forget that too. And good for you. These companies are snubbing themselves right out of business. It's only a matter of time before the .308 AR standard is set, and I'm betting DPMS pattern. Heck, it already is.