I shoot 223 in a couple of guns, one a Savage bolt action where I neck size and trim all my brass. The other an AR. Need I trim the AR brass? I's only used for target shooting. I thought I read somwhere that for general plinking etc it's not necessary to trim. Whatta you people think? If I am shooting the AR for competition, then I would trim etc all my cases, but what about just plinking and target shooting? Thanks for the advice.