Jason, I know what you mean about brass prep. That is part of what I like about shooting Lapua brass in the Grendel. I am at 5 loadings and have not annealed or trimmed the brass yet and am still in spec in measuring those loads. There are some that shoot a lot more than I do that report throwing away brass they never trimmed and had 20 firings on it. Guess that is an advantage using 52000psi max loads in brass that could handle 60000psi without an issue. Some that are loading to the 60k for their boltactions are saying brass life is reduced to 7 or 8 firings.
There have been concerns about PPU and Wolf 6.5 Grendel ammo for a while, reported on several other forums. Now PPU is blaming the guns while their ammo is undersized according to SAAMI specifications. Head space SAAMI dimension for headspace is 1.220 -.007 measured at the .350 datum on the shoulder PPU brass on new loaded ammo is often in the .006 to .008 under SAAMI minimum dimension. Combine that with a chamber that is SAAMI max and that could be an issue resulting in high chamber pressure.
We know ammo manufactures often make ammo at or slightly below SAAMI specs as Hornady does but their headspace dimensions are 1 to 2 thousandths below SAAMI minimum not 8.
Spot checking some new Nosler and Lapua brass I have here, it runs right along with Hornady on headspace being just under min SAAMI specs. This goes right along with some others that have measured and posted on other forums. Some of the ones in the links below are gun manufactures and one is co-author of the Grendel load data manuals. Link
In RickOshay post there is a link which has a link to another discussion on PPU ammo pressure issues and in that post there is a link to another.