Well as a resident new guy I will give my evidence, I started with a 22-250 rifle that was just one in a million accurate out of the box. With a skim bed job only, no trick parts at all it shot mid ones to mid twos off a bench at 100yds 3 shot extreme spread less caliber dia. They were loads with powder, charge, primer type, and bullet arrived at thru trial error.
The brass happened to be Winchester which I did what I call match prepped (weight sorted-primer flash holes deburred-trimmed-and necks checked and chamber formed) I was stupid lucky and it worked. Someone asked if I had tried Lapua the best brass out there, hmm I got some and tried the exact same load in them, it shot threes to fours
now I didn't try tweaking all the other parts of the load I had already dialed in so my bad I guess. Shooting buddy said go back to Winchester and call it good,I did. Not scientific but very result driven.
Next caliber I started with Winchester brass and some Norma I came across,the loads worked better in the Norma. No pattern for sure I thought, Next two calibers loved Lapua, I'm confused now cause I'm trying other brass also each time. can't find one to go with it seems.
Lapua is easier to weight sort and closer in weight, Norma don't last as well as Winchester and Lapua. This reloading never gets boring. My gunsmith friend talks about case capacity and pressures being different, I imagine a lot of posters on this site know better than me, All I can say is that I'm result driven and I can't find one brand of brass that's always better. Dave