Everyone serious about shooting and developing loads should read "The Secrets of the Huston Warehouse"
In addition, read this:
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA542434
The above link is about testing military ammo, besides case prep it was discovered that getting the bullet seated staight in the case is critical.
The link confirms the findings in the Secrets of the Hustion Warehouse.