rt_con
Since I switched to mostly harvester sabots and indexing carefully I have had very few unexplainable fliers. That is not to say I don't throw one once in a while. To me the difference between a flier and a thrown shot is I know what caused the thrown shot I may never know what caused the flier.
On indexing the sabot, stop and think about it. The rifling and the sabot are both symmetrical the gap between the petals is big enough to take a rifling if only 4 rifling's are pressing against the bullet it will have less pressure holding it in place so when the powder starts to burn it will moves easier and sooner different powder burn different pressure = some difference in the POI.
Now I realize this is just my opinion and each of us may have a different one; I wish we could all get together see just what ideas would prove themselves on some targets.
Lee