For many years I shot only Norma brass in my 220, and it was a wonderful shooting rifle. I switched to Winchester (I don't know why, but must've been $) and it still shoots great but maybe not as great. I say maybe because I'm older now and I'm not sure the brass is the reason for slightly larger groups. I'm sure some of you grandpaws know what I mean. So anyway, I needed new brass for my 270 and I splurged and got some Norma. Probably the brass didn't need any prep, but I did it anyway and also turned the necks just a teeny bit. I'm retired. I've got time. So today I just started with the load I've been using for years in that 270 in Remington brass and good heavens, I got great results. Geez! It was like making a great shot in golf and nobody was watching. I even went into the house and told my wife, and she says "that's nice, honey". So I thought I'd tell you guys.
I'll do more shooting this week and see what I can really do groupwise.