But this is best-possible scenario.
•It assumes that conspirators (shooters or planters) know all about WCC/MC ammunition. This low probability is completely unavoidable.
•Drops by another factor of 10 to 100 if other ammunition is used. (Becomes 1/105 to 1/107.)
•Drops to 0 if hardened lead cores are used.
•Result: Chance groupings ruled out.