brass raw material quality , too soft is bad , too brittle is bad
draw cocentricy between ou side and inside wall
weight uniformity that generate variation of wall thickeness
primer pocket quality ( tight and round ) depght can be recut so that not a real problem
flash hole size , cocentricy to primer pocket
head squareness to allow to get a perfect sqaure head to bore axis
brass anneal quality ( unformity in teh same batch )
all this prameter allow you to get match brass
some parameters can be get by sorting as exemple on my 6.5/300 DTC Yuma I use 300 WIN mag case ( Winchester brand ) that I sort by weight after forming so I can remove weight variataion , I ream flash hole deburr inside and check during neck turning real uncocentric neck . so I get not too bad case for LR
main problem is raw brass quality the very best is SAKO ( but costly as gold ) Lapua is very good , RWS is very hard brass but quality is good , Norma is very soft
that because you need before to choice one cahmebring to check what qulaity of brass you can get and at what price , sorting case is always possible but purchase a batch of case at 0.5 buck each is more easy for the wallet that case at 2 buck piece ...
good shooting
DAN TEC