Here are my stats with my Alpha brass:
31.6 First shot of the day was like 2840 so I removed it from the Velocity Stats {Avg 2880, SD 6.1, 5 Shot with magneeto attached @ 100 .613 MOA},
31.8 {Avg 2886, SD 2.6, 5 Shot with magneeto attached @ 100 .525 MOA},
32 {Avg 2900, SD 4.6, 5 Shot with magneeto attached @ 100 .32 MOA},
32.2 {Avg 2914, SD 2.2, 5 Shot with magneeto attached @ 100 .5 MOA},
32.4 {Avg 2926, SD 2.8, 5 Shot with magneeto attached @ 100 .323 MOA},
32.6 {Avg 2938, SD 2.8, 5 Shot with magneeto attached @ 100 .331 MOA}
I had loaded up 32.8, 33 and 33.2 but 32.6 gave me a heavy bolt lift and the lowest charge had ejector marks so I left them unfired.
I guess I need to try the shenanigans of loading up a softer charge for the first firing to try to hearden them up, IDK. SD's are great and groups are good.
Here is the 600 yard ladder:
1 = 31.6
2 = 31.8
3 = 32
4 = 32.2
5 = 32.4
6 = 32.6
I just got back from the range so I haven't checked what the headspace changes were. I didn't have any problems with Lapua brass, other then needing to fireform them, IIRC the Lapua had mid to upper single digit SD's, though those may have been 10 shot strings.