DO NOT TURN THE TUBE!!!!
Its the nut that needs to be turned.
Hold the forearm, and turn the nut...yes it looks like 1 pc but its not.
The nut is separate from the barrel nut.
Go here, 2nd page and you will see that its not attached to the barrel nut either.
Good info on removal of forearm.
http://mossbergowners.com/forum/index.php?threads/removing-the-mmr-hunter-handguard.6665/page-2
The gas block is held on w/tapered pins and only come out 1 way. You will need a small drift punch to get them out, may stick but mine came out easy enough. The gas tube is CARBINE length also. I thought it would be mid or rifle but its not.
