His take was the non annealed brass had more spring back(brass wanted to return to fired diameter after sizing). Which resulted in less neck tension/ lower seating force.
Look at the season long aggregates to 1000-Benchrest results, and much of what your wanting to see is readily available.I would love to see the AMP annealer tested under firing line conditions. The real test of annealing is if it improves the ability of putting holes in paper. Some test tunnel time in regard to accuracy and case life would be nice to see. Until then the physics of how metal reacts to stress has been around for a while now and just bewcasue the metal has a Lapua stamp on it does not alter the laws of nature
In my experience, running a nylon brush in and out of the neck of a fired case four times will only take out the loose powder fouling, and does not come anywhere near taking it all out.Unless I misread what took place there was less force needed to seat the bullet when the carbon was removed. I always thought that the carbon in the neck acted like a lubricant making bullet seating easier thus giving more consistent neck tension.
But at the same time you can look at results of others that don't anneal with similar aggregate capability, which proves there is no "law of nature" when it comes to cartridge brass, and that there is no single right way with cartridge brass, as to anneal or not to anneal.
Just my 2-Cents
The elastic deformation of a metal is a reversible occurrence where the metal can return to its original state. Metals that are deformed past the point where a return to their original state is impossible are referred to as being plastically deformed and not elastic. When stress or strain (tension or compression) is applied to a metal, a series of forces act on the metal forcing it to expand in an axial or radial formation - essentially elongating itself. If the applied stress or strain is within the force load allowances for the given metal based on its modulus of elasticity then the metal is said to be elastic and it will return to its original form when the forces are removed. If the applied stress or strain is greater that the modulus of elasticity determined range then the metal will be permanently deformed.
https://www.corrosionpedia.com/definition/6370/elasticity-of-metal