You will hear about trimming both ways. I never trimmed, then I got into some competitive shooting, and some said to trim, and some said no real need to. So I did 500 none trimmed and 500 trimmed to exact specs. I ended up not shooting any more or any less accurate. Gave 100 of my none trimmed to a friend that shoots competitive and he shot no better or worse with my none trimmed and his trimmed loads. This is just like the chasing the lands, full length size everytime, bump the shoulder, or neck size only arguments that go on all the time.When it comes down to it, whatever helps with accuracy and what a person is comfortable with is the way they should do it.