All I did was to pass along info stated by a technician wring n a Ballistics Lab, I suspect he knew a bit more about the subject than Me, You & Wonko combined. Follow it or ignore it, no skin off my back either way, I just passed it along.
The problem here is I think two fold & does make perfect sense.
1st, when the crimp folds down around the projecting petals of the wad it creates a resistance to the wads moving
2nd, with the light shot load the wad is not compressed to its normal extent leaving the wad "Stiffer" than normal.
According to this lab this has definitely been "Proven" to raise pressures to a excessive level. Do with it as you Jolly Well please, personally I will follow their advise.
