Lee
my only guess is that it over pressures the nipple
OK! see i was wondering the same thing... to much pressure and heat trying to get through that flash-hole... I can not come up with anything other than that... OR could it be that the Federal, being the strongest 209, is actually pushing the sabot off the powder creating a short air space, and since BH is a progressive burning powder that air space is hendering the ignition of the main powder charge???? Just a thought out of the blue.