Unknown 50m and 100m accuracy and harmonics

What started as a normal slug test actually taught me a different lesson. Harmonics. Today I shot the brand new Unknown Slugs fromSouth Africa, available in .217 only. 22gr, 26gr and 30gr. Shooting them at 50m and 100m.
Gun Set up:
700mm Superior Heavy slug liner with Power Plenum
Reg @ 140bar
Valve at 3
Dual Flow Port and Pin Probe installed
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