I've always trimmed then sized new Win brass. Used to buy it by the thousands cheaply on sale at Midway in the 80's and into the 90's. Always had great luck with accuracy, primer pockets staying tight, etc. In fact, I still have the bulk of that Win brass (mostly 223 Rem) today.
In the past year or two I've bought several new batches of Win .223 from different vendors. I was very
disappointed in the lack of consistancy in the brass. The primer pockets were especially sloppy with tightness ranging from so loose I swore the primers would fall out to
so tight it was like GI brass with the pocket crimp in place.
Maybe I got spoiled by Lapua brass in the last couple years but I don't think so. I've loaded so many thousands of .223 of various brands and never used to have a problem with Win until recently.
Not going to buy any more Win brass and Rem has not been on my favorite list for a long time. Just wish Lapua was cheaper.