This came up on another thread, but since you asked...
This is the load I worked up for my 209x50 Encore:
3-50/50 pyro pellets
1-220gr. " Dead Center" polymer tipped sabot ( made by Precision Rifle Bullet )
1-Winchester 209 shotgun primer (though I am considering the .410 primer)

With this load I am consistently patterning 1.5 m.o.a.@ 100yds. off of a rest.

Good Luck & Good Hunting