One interesting lesson I learned.
I was very diligent and careful doing my first reloads, spent about 2 hours to load 60 rounds on Lee Turret pres. Checked powder load on every 10th case.
I already new that empty brass weight is inconsistent, but out of curiosity decided to check weights of all 60 loaded rounds.
Most rounds weight was in range 190.0 - 191.6 grains, but one sucker was 187.0 grains. It was scary, did I miss a powder load (which in my case was 3.9-4.0)?
So, I pulled the bullet out - hmm, powder was in place. So I checked weight of the empty brass case and yes - it was 3-4 grains lighter than other empty cases.
(All my brass was once fired Blazer Brass).