Interesting you mention that.
I was working through a bunch of .30-06 brass for my M1 this weekend. I picked up 30 Hornady cases in a batch that I bought, and... well, they felt light. So I threw a few on the scale...
Hor: 177grn
RP: 200grn
FC: 205grn
...the FC was almost 30grn heavier! What that means to me is the Hornady brass is likely thinner, which isn't a good thing in an M1 Garand. Further, and assuming it also means greater volume, it will likely translate to less velocity. It could also mean the necks are thinner, which could affect other aspects of my handloads, including neck tension. Just food for thought.