hi,
you will need right tool. space is very narrow to fit classic dd wrench or clones. dont even try use them
because barrel nut is made of soft aluminium. you will need devide torque force in all 4 teeth to avoid nut damage. so will need something like this. i did it yesterday. i am lucky cos had no glue on thread. but in all cases use hair dryer or flame torch(very carefull) to melt thread glue a bit. it looks like TM use glue very randomly. someone have yellow one, someone have red.