I have a 257 Roberts barrel on it now from the Custom Shop.
I really like that caliber. I have a 22 Hornet barrel on order from the C/S as well.
Just shot the Roberts today. My varmit load uses a 75g. Sierra HP over H380. My smallest 3 shot group has been .420" Today was a 4 shot group at 5/8".
I have been working on a load using the 100g. TSX bullets.
Last week, I shot a 3 shot group at 1/4", but today it opened up. Seating depth seems to be very critical with this bullet.
I have a Dillon 550B as well, but use it only to load 9mm,45acp, and 223 for my AR. My Encore stuff is done one at a time, but I would think you could use a body die in the third station and that would work.