That question is like asking how long is a piece of string...and gets into a lot of misconceptions and personal thoughts and prejudices...nebulous to say the least even though it seems a simple and innocent question...
No way to answer that question without a major amount of testing equipment and even then it will only hold for the individual barrel being tested.
It's as simple and as complicated as why will one rifle shoot one particular load combination into one hole and another rifle will scatter the load into a pattern...
Reason is ALL barrels have an individual resonance or vibration harmonic...doesn't matter what brand or type of action...what type of steel it is made of...how long...how thick or thin and so forth.
Putting in a dampening screw may or may not help...you may or may not hit a node (point of least vibration)...if you do it probably won't do much. But if you hit a point of maximum vibration then the screw will act as a damper and change the harmonics(basically move the harmonics to a different spot)...you don't know for sure until you do it...and it might or might not help.
I usually free float the forend first...O rings help for a while but they are rubber and will collapse after a while so I don't use them...I install an aluminum pillar with epoxy, change to a button head screw and use a metal washer instead of the rubber one and torque to 50-60 in lbs. I also bed the barrel to the receiver and shim the hinge pin to reduce the headspace and slop along with making an AL fore end spacer and shimming that if needed.
If that doesn't seem to help, I epoxy in a not quite full length AL 1/2" x 1/2" bedding block, full length epoxy bed the fore arm and again torque the screw to 50-60 in lbs...one or the other usually works for me. You can also experiment with the torque amounts and tune the groups somewhat.
I used a screw in a HB Ruger #1 25-06 after I had used up all the tricks I knew with bedding and ammo prepping...the screw worked.
There are also some bedding tricks like the sliding wedge that could be adapted or copied that will work.
All this work isn't worth a plug nickel if your ammo isn't accurate to begin with, so many times it isn't the fore arm that is the cuplrit it is lousy reloading practices and limited understanding of the whole process as a SYSTEM...not as individual items to be messed with, hit or miss. AND... if you don't accurize the WHOLE system as a step by step process before trying to target...you are just whizzing into the wind.
It takes work to get ANY type of rifle to shoot accurately and many times...UNREALISTIC expectations put the fly in the pie. The NEF is a very "inexpensive" shooter so don't expect miracles...it will never by a benchrester but you can get the accuracy down to bug holer with a little work with some calibers and 1" or less for the larger cals.
How to accurize the NEF is covered by Fred in the sticky's...check him out.
Luck on your quest.
