Instructions provided by CMMG.
Disassembly instructions. For qualified gunsmith only!
Unload and disassemble the PS90 and secure the barreled receiver in a drill press.
I used a #43 carbide bit and drilled out the blind pin.
Using barrel blocks, clamp the barrel into a vise. You can then slip a 15mm wrench onto the chamber end of the barrel.
A stardard size wrench will not fit, so you have to thin it down a bit in order for it to work.
The barrel/flash hider is left hand thread, so turn the wrench clockwise to break it free.
The barrel is now loose from the hider/sleeve and you can now slide it off.
(Continued next post)