Yeh I know there is another thread talking about barrel nut torque right now and it is a good one.
I am thinking about best practices and best results.
Plus I know from nearly 50 years of using torque wrenches that the torque should always be quoted dry or with lube/antisieze.
Serious question for you builders, does the barrel nut torque affect accuracy?
I have seen specs between 35 and 85 ft lbs torque used, that is a HUGE range.
Throw in that the torque value is different depending on what kind of lube is used, and that there are steel and aluminum barrel nuts.
Obviously a free floating tube allow nothing to interfere with the barrels harmonics. So the only thing that touches the reciever is the barrel nut and how tight it is.
I am putting a nice barrel on a heavy duty upper reciever, and will be using a Clark Custom rifle length carbon fiber tube. The barrel nut is aluminum, so I am using special antisieze (silver) as I do not trust over torquing aluminum on aluminum.
Regarding accuracy, I would venture the impact if the barrel was installed correctly is minimal [READ - you won’t notice it] as long as you are within the given torque range.
For precision builds, instead of playing around with torque values (just keep them within the specified 30-80 ft-lb), what you could do is to loctite the barrel extension into the receiver before you torque down the barrel nut. I know some people will also use loctite on the barrel nut, but that seems pointless to me as I’ve never heard about a barrel nut shearing through the gas tube.