Sorry for the newbie question but I just got my barrel from TROS and was installing it when I could not figure out how to tightenin down the barrel to 30-35 ft lbs. I know you need a 15 mm wrench on the chamber end but how do you secure the flash hider from gouging the receiver as you torque it down (gen 2 fn flash hider). I saw in the barrel swap thread to use a thin piece of brass or aluminum. Is this the best practice? In addition if I do not torque it down to that limit what could happen? I plan on interchanging between the factory fh and the TROS adapter. Thanks for the help.