The relax point is real and occurs in a 30-06 bolt gun at 16 inches average, depending very slightly on the powder number commensurate for the projectile. It is the point where the ACCELERATION of the pressure expansion reverses direction. The point was determined experimentally by some American Rifleman author doing barrel chops, 1/2 inch at a time. Noticed was the difference by the shifting of the copper fouling, much like the antimony wash appearance when and where. Obviously, revolter barrels will have a much shorter distance from the chamber where this phenomenon will occur. ... felix