I have a Fulton Armory mirage upper (service match style) with float tube that I am going to change the barrel on, do you need to remove the float tube seperate, is it threaded onto the barrel nut. Or does it come off as a 1 piece unit by just turning the barrel nut?

Thanks

If you can get a barrel wrench into the star nut, then yes you could just pull the whole thing as a single unit.  

Myself, I break down my tubes down so when I reinstall the tube, I can re-index the float tubes to keep the swivel at dead bottom.   Also, depending on the amount of wear to the hand guards, you may be able to thread the tube one more thread to tighten them back up.

Note: On the DCM tubes, you have three parts.  The barrel nut, the float tube, and a tube retaining nut to keep the tube from spinning on the barrel nut.

Can you give me the procedure to break them down.
Thanks

With the upper vised in an upper block, start with the front sight tower.  You will need to take out the four allen head screws and pull the front sight tower straight off (twisting will bend the gas tube). You can pull the gas tube off the front sight, but normal I don’t remove it to change out barrels.

Now loosen the tube’s retainer nut (small ring in the middle of the threads on the tube section) and spin the tube section off the barrel nut. At this point the barrel nut will be the only thing left, which needs to be removed to pull the barrel.

Note: If you are problems loosing any of the parts, they will need to be heated with a heat gun to break any loctite that may have been applied.

Tools needed,
Upper vise block
Retainer nut wrench
Barrel nut wrench
Allen wrench
? Heat gun