redgreen

Falcon has it right there. I have one weatherby load that is 5 grains above maximum, and is extremely accurate, but not over pressuring at all. There is still lots of radius around the primer pocket, and the brass is checked with a micrometer after firing on all of my test loads.It is also chronographed. If you are full length resizing all of your brass, and moving your shoulder back, then the case is flopping around in the chamber, and when you fire it, the primer will back out and then when the case expands it will flatten the primer as it pushes it back into the case. Each rifle is an individual. A handload that is efficient in one can be a grossly overloaded bomb in another, due to differences in chamber specs and bore diameter. One of my rifles was overloaded at 4 grains below book max,due to an extremely tight chamber and bore. The velocity was incredible at book max, but there was no radius left around the primer pocket, and the case head swelled .0007. Those manuals are a guideline, not gospel.