You make it sound, Oh, so simple!
That's because it is.
I have found that many pieces of WW 7WSM brass have dinged or out of round case mouths, hence the reason why I run them through the sizer before loading them.
How is neck-sizing 7WSM brass different from creating a false shoulder in .300WSM brass? It's the same process. My "fire-forming loads" are every bit as accurate as my main loads, and I'm getting 3050fps from a 140gr bullet, aka .280Rem performance. Even my fire-forming loads kill stuff dead, and ring the gong with impressive accuracy. I was out shooting at a dinner plate-sized rock a month or two back at 1120 yards with my fire-forming loads. Didn't seem to have a problem smacking it. My full-house loads get that 140gr bullet to 3295fps, and those are what I typically use for hunting.
Works just fine for me, and all my loads turn in MOA or better accuracy. Brass forms just fine like this, and I'm on 4x firing one particular batch of FF brass, and it's still going strong (could use another annealing, perhaps).
