Headstamps and primer sizes

[toolsofthetrade]

OK, just getting into this whole Grendel thing :cool: got my rifle, bought a bunch of ammo from some guy, just for the brass, shot some had pressure signs, stopped firing it, pulled it all, went to reload and found that there are two types of brass here, AA (Alexander arms), small primer and PPU (which is wolf by Prvi PArtizan right?) large primer.
So what brands have what size primers, I would like to stay consistent with my brass.
Anyone want to trade some PPU for some AA or other small primer brass? I have 84 pcs of PPU!?
Has one been found to be better than the other (small vs large primers)?
TIA

[bwaites]

Small primer is generally accepted as more desirable. Doubtful that anyone would trade Privi for either of the 2 small primer brasses, Hornady or Lapua. Those are the three options.

[z06man]

Why is small primer more desirable?

[longdayjake]

Small primer holes don't expand as soon. You get longer brass life.