Nosler brass in 300 win mag is very hit and miss. Reference this thread
Nosler 300 Win Mag brass, very unimpressed!!!!!
I got a box that had some case head anomalies
and after contacting Nosler they sent me another box. That box had variances in neck thickness from .009" to .017", and that was on one case!!! All of them had a very thick side and a very thin side.
I have the box ready to send back to Nosler but I am giving them an opportunity to fix their QC issues with the 300 win mag brass first.
That being said, I just bought a box of 30-06 Nosler brass that was just fine and the neck thickness varied from .013" to .014". Buy the box and load them right up, no prep. I also use Nosler for my 280AI and it has been very good.