With regard to another thread on this forum discussing how much torque to apply when tightening a barrel to the receiver, I found chapter 6, Barrel-Receiver Threaded Joint Motion to be particularly interesting.
In this chapter, the author discusses measuring barrel movement shot to shot and resultant flyers, and how barrel torque and barrel thread design affects the degree of movement.
He found a torque of 200 ft lbs to achieve a preload of 20,000 lbs to be impractical due to barrel wrench failure, and the required preload to be impossible due to thread failure due to the limits of the V-thread design and steel used, as well as the recoil lug steel.
In summation, the barrel to receiver joint moves shot to shot in most every rifle. Heavy barrels help this by moderating the temperature gradient between chamber wall and receiver threads which tend to loosen the grip the receiver has on the barrel, but it does not stop movement.
Part of the reason for this is that only the first few threads of the receiver/barrel joint take most of the load with the rear most threads taking almost nothing.
This reminds of Virgil King's insistence that lapping the threads in on a new barrel installation was necessary to spread the load across the threads better. Seems he was a couple of decades ahead of Vaughn
RG
