That 300WM fed by a 10 round mag is pretty cool. Plenty accurate for me, but seemed really finicky about the ammo it would cycle. I would expect a $5000+ rifle to eat anything I put in it. I also think that if a manufacturer sends extra parts with the rifle (i.e. extractors), there must be something to it. The first couple are free, but then you pay after that. You have to be pretty stable when you fire it, because if your body rolls with the recoil very much, the bolt won't cycle all the way and you end up with a double feed or a smashed/dented top round in the mag. It really marks up the brass, too. Large gouges and dented case mouths. The theory is GREAT, but in my experience, the practical application isn't all that