[Trikstr]

SSK AR-15 upper
16.25" 1:8 twist

220 Sierra MK
9.2 grn IMR 4227
Rem 7 1/2 primer
OAL 2.222"
221 FB case capacity 24.2 grn H2O
1-800 fps
2-876
3-893
4-824
5-865
ES 93
SD 36


220 SMK
9.7 IMR 4227
Rem 7 1/2
221 FB case
OAL 2.224"
1-903
2-936
3-883
4-935
5-890
ES 53
SD24
Case Capacity 24.2 grains H2O

220 SMK
9.7 IMR 4227
Rem 7 1/2
OAL 2.224"
1-938
2-936
3-890
4-961
5-903
ES 74
SD 30
Case capacity 23.2 grn H20/reformed 223 Headstamp CJ8

220 SMK
10.2 grn IMR 4227
Rem 7 1/2
221 FB case cap 24.2 grn H2O
OAL 2.110"
1-1098
2-1098
3-1107
4-1090
5-1088
ES 19
SD 07

None of these grouped especially well. I'm going to weight sort my cases.
The last loads I shot with AA1680 I noticed vertical stringing and I think it was caused by variations in case capacity.