Far be it for me to say this is 100% correct, but I've been told that after the case is formed, the primer is is placed, in liquid form. After it sets up, (pretty quick) the powder and bullet are added. Again, I've never seen it done, but it sounds good.
"For those who fought for it, freedom has a flavor the protected cannot taste."
"USMC 8652, 2531, RVN Jun '67, - May 69"