Now you have my attention. You say 2.1 BE. with a 100 grain SWC and getting fantastic accuracy out to 50yards.
1. Is this a cast boolit or swaged?
2. What is the actual oal of loaded round?
3 Roll crimp or taper crimp
4. What kind of groups are you getting, center to center?
5. Getting any tipping?
6. Any idea of velocity?
7. What kind of brass?
8. What primer?
7. Shot from machine rest,bench rest?