Originally Posted By 6530:
OK, here's a dumb question. Why wouldn't once-fired brass need resizing/trimming? Or does it need FL resizing but no trimming? Or does it need both?
Not a dumb question...
It will certainly require resizing, and I would recommend full-length resizing the first time since you won't know what chamber it came out of. After it's been through your rifle you can just re-size the neck.
What Z1500 said is that it doesn't require trimming, which is entirely possible with quality once-fired brass. It should still be spot-checked at the very least with a case gauge. After a couple of firings, .223 brass should be checked, as it will start to flow, especially if you reload with a cannelured bullet and use a crimp die.