Well, I did't say I removed every variable but I do seperate by type, lot, etc. Yes, new brass would be the best way to go but I also have a budget to stay within. Small variables, when combined, become large variables. Ultimate accuracy would be great but I'm 5k short of the proper rifle. So, I stick to small variables.
Lol, when you bring unknown components in to reload for accurate shooting you are adding more variables than taking away. When you have no knowledge of how many lots of brass you picked up. Its your horse, Saddle It any way you want.