Rifle brass does "grow", and needs to be trimmed. It is best trimmed after it is resized. If you are going to use military brass, it does need the primer pockets either swagged or reamed to relieve the crimp ring. I have used the Dillon swagger very well and it does a good job.

If you are shooting for accuracy over long ranges, you should start with new brass from the same lot, ream the flash hole (inside), uniform ream the primer pocket, resize, Trim, de-burr case neck and then you are ready to load. For .223 I would plan of trimming at least every other loading.

I bought a RCBS Prep center a few years ago, and am well satisfied. I use a RCBS trimmer, but removed the handle and attached my cordless drill.

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H Richard
SWCA1967 SWHF244