Good question 303guy and the idea of standard format free floating .303 barrels and accuracy have been aired on this site in some depth previously. If I just say that all a thin barrel is, is a tube or a cylindrical tuning fork in relation to its harmonic properties. And the bullet doesn't give a toss about what has happened or is happening where it's already passed. The only thing that can affect it up the bore is what is happening ahead of it. And guess what's happening up ahead of the bore......... Yep, vibration and plenty of it! The best thing to cure this vibration is to damp it down in a controlled manner. Are things fitting into place now............ ? Are you thinking of a muzzle bearing.......?
I hear all about the accuracy of free floating barrels - sometimes listening/reading with eyes as wide as soup plates, mouth agog! But I step back and just ask myself, as others might, this pertinent question......
If accuracy like this could be obtained with all these super-duper san-fandanglio methods of fitting up fore-ends which wera all exhaustively tried, trialled and tested and the results detailed and published, then WHY was the fitting of the fore-end on the No4 rifle NEVER relaxed (actually, it was, once for a short period during the war to allow for the dearth of good timber). And another aside question too......... Why was the fitting of the accurate No4T forened NEVER, ever relaxed.
Just a few points to ponder
PS. Please don't take every word of this as scientifically correct as it's not but I've skimped over things to make it short and sharp but to the point.
Someone ought to ask me about that side mounted telescopic sight mount next. Don't forget to mention clock and anti clockwise moments/torque too..........