i am shooting 165 sst with 71.5 RL 19 and after they are shot when i re size the case the back of the case is still to fat. the primers are not flat
and i am fairley new to reloading not sure what to do..

Are you using a full length (FL) die and have it screwed down to where the bottom of the die cams on the top of the shell holder? And are you sure you have the right die? It's not a 300 Win Mag or something else is it? There are lots of calibers that start with .300 . . . .

How much bigger is the back of the resized case than on an unfired case. And, comparing it to a fired case; does the back of the case get bigger after you resize it?

i am using a full length die and it is for a 300wsm. the end of the fired case is about 5-6 thous. larger after resizeing. i am using rcbs dies.
somebody mention using a undersized die for is but where do you get those?

Do you cam over? You know set the die 1/4 turn more after it hitting the shellholder?

After you fire and eject the shell, could you put the shell back in and chamber it?

If you can't then your chamber is slopped up. Now if your just concerned cause your case isn't perfectly flat, don't worry about it. In all honesty, however, near the rim of the case should exceed .004" of that caliber after firing compared to it before.

found the problem, the decapping and neck size pin was out too far.
that was really dumb!!!