As you ask it, your question is impossible to answer. #1 we are blessed with a plethora of good bullets to choose from, and #2 your barrel will dictate what is best and different Omegas have different personalities -- what works in my gun may not work in yours.

As you are new, I recommend you either get a 25ACP conversion breech plug to shoot 777, use the 209 primers specifically developed for 777, or use BH209.

As for bullets, anything out there in the 250gr range is good though I also like the 200s for deer and use them more.

The range you expect to shoot at, as well as game animal, will also affect your choice.