Before everyone slams you for having your post in the wrong spot, next time put it in the reloading area, and not the for sale of reloading goodies. No big deal.
Now on to your question. What makes good brass? Something that is consistent and lasts. Some guys start by sorting brass into different weight catagories with the idea of if it has the same weight it should have the same internal case capacity. Some guys will actually weight the internal capacity. Most of these guys are BR shooters. Next is the amount of prep work that goes into the case. Uniforming the primer pocket, debuting flash hole, ect. After all the fun work is done and you start shooting some shooters will like or hate brass based on its ability for better ES on your velocity, and it's ability to have repeatable results shot after shot. What I mean by this is some brass will become work harden after 2-3 shots and some have better case life. Some companies primer pockets start to get loose, or case mouth will crack.
These days, especially in 300 mag, take what you can get. But if your lucky and you find RWS brass or Norma, that is a good buy.
Hope this helps.
