One of our testers, Bret in MN, got the BPI Sabot with
500gr Hornady .500 slug up to the good speed listed
on BPI"s loading sheet, using shotgun powders. I could
get them there with my loads using much larger amounts
of rifle powders. He tested 3.5" Federal plastic cases in
his Savage 210 with 3.5" chamber and the 28" heavy barrel
he put on. With 50gr of Longshot(max load for all modern
guns) he got 2550 fps, with 500gr in sabot. He use two
BPGS gas seals fitted together over the powder, then
a FS12 Flexseal wad, then a 1/4" cork wad, then the sabot.

Then a good strong roll crimp with drill/drillpress crimper.
This load is at mag shotgun pressures by case expansion
measurements and BPI's 46gr load tested at 12,500 psi.
He also did one with one BPGS and two Flexseals and had
200 fps less.He had tried other combinations seals/wads
and with same amount of powder and got lower yet.
He also went up with the powder, with seal/wads that worked
the best and got about 3000 fps, but the plastic cases
stuck and wouldn't eject easy. I will be testing same
seal and wad column in a few days, in my NEF with long
barrel to compare results.I thank Bret, he is a real
good experimenter and idea man. Everybody is trying
like crazy to get that 500gr saboted slug up to big
game gun velocities with shotgun powder and thanks to
BPI"s supply of the right components it has happened.Ed