Ryan_F

Stick the nub on the wrench in the hole on the barrel nut and rotate:

Yes - if you read the text above too quickly you come up with a very different sentence....😜
 
Alternative methods (for bodging it and probably inflicting some kind of damage):
- Vice grips
- Stick the nut in a bench vice and rotate the receiver
- A drill bit of identical size to the hole, into the hole, and try twisting it off by hand