Originally Posted by
Jhon
Quote: "What part of the case will fail with FL resizing? I take it that the brass splits down the side? I thought the neck would be the first place to fail, but i take it that annealing largely addresses this, can the whole case be annealed at all?" Endquote.
First never anneal past the shoulder. If you do you will tend to get unpleasant results like case length crushing when you seat bullets.
Second, if you anneal the case neck you extend the reload life of the the case and enable correct neck tension on the bullet. If the brass is too brittle and hard it not only splits but it springs back when resized so neck tension is less and not uniform case to case.
Third, the case will eventually fail if not from neck splits then two other things. If full house loads the primer pockets eventually won't hold a primer tight. Same in all cals..with 303B brass, before primer pockets fail you are likely to get case head separation. Especially if you FL.size for a generous chamber and larger headspace dimensions. To check for incipient head separation use a thin wire, folded out paper clip, with a small hook bent on one end. Insert in case head and draw forward, hook against case wall. A short distance from the head, maybe 4-5mm, you may feel the hook catch. The brass has thinned here forming an internal groove. On the outside opposite the groove you can usually discern a shiny ring. If either it is time to discard the case or risk it rupturing and separating head from body the next time you fire it. 303B brass is well known for this. Not such a problem if you are loading down and neck sizing. Primer pockets dont stretch as much either.
The cases only tend to split down the side if the brass is old, rotten or really tired and brittle. Hot loads will do this with old brass like some of the HXP and old 1940s-50s CAC etc. Young brass like factory PMC, Hornady etc likely won't give you side splits. You'll get split necks, case head separation or loose primer pockets prior. Long life for 303B comes from good brass, annealing, neck sizing and modest charges.