Anyone else come across "short" 300 RUM brass?

So all my new 300 Ultra brass I just bought measures 2.830 instead of the 2.850 that it is supposed to be. It is Remington brand. Anyone else come across this and do you think it is even anything to worry about? I'm assuming it will "grow" a bit when I shoot it the first time.
Any suggestions.

This is for an Edge, I forgot to mention that. The measuring took place after I opened up the necks, didn't think about measuring it before hand so I don't know if sizing them just pushed them down a bit. I was no where near the shoulder of the die when I sized the necks so I didn't "bump" it back.

Thanks

Any time I open brass up, the length decreases. When I open up 30-06 brass for my 338-06, it always comes out shorter than spec. I haven't checked my 338 Edge but I would assume that it "shrinks" too.