The best way to save your brass is to set your sizing die to just "kiss" the shoulder( smoke neck/shoulder area with a lighter/candle then you can see what is going on),especially on belted and rimmed cases. Since these technically headspace on something other than the shoulder, setting the dies as often done, sets the shoulder back. When the shoulder is moved back every time it is fired, it stretches and when it does it thins. When it does this several times, the case will fail. Having to trim the case every time, should be the first sign the dies need to be properly adjusted.
Mike
