4759 is a very good all around powder. If you can find more get it. I like VV N110 the best if shooting mostly 250gr bullets. N110 is a bit hard on sabots. The rise to peak pressure is pretty fast. Ive had my best luck with it by not going over 41gr. It produces excellent speed too.
Reloder7 is easy to find and works really well with a 300gr bullet. Its cheap, easy to ignite and very easy on sabots.
VV N120 is awesome with a 275gr to 300gr but its nearly impossible to find now. Ive heard rumors that its being imported again. Excellent speed and really clean.
One of these sabots should work for you. Most of the other sabots are probably a bit too loose.
MMP short black sabot
MMP HPH12 sabot
Harvester RED Crushrib for smokeless
Get a box of cheap 250gr or 300gr XTPs. Not the 240gr XTP mags. Use these to get it sighted in and for getting used to the MLII. They will kill deer just fine too. Once you get it shooting good buy some Barnes or other highend bullets.
