The expert was positive that his EZ load sabot had moved just a little off the powder charge.
Wow, I do not want to have that to worry about. I have only had 2 sabot shooters, both load very hard, and I have never missed a deer with them, so I have never questioned whether my sabot/bullet had moved off the charge.
On the other hand, my many years of Maxi-Ball hunting, I would check every time I moved from place to place. I found that it had moved once, but that was on a mild/rainy day.