200 yrds is a long shot for any ML. If you can hit a deer at 200 yrds in the kill zone you would be eating venision, but ML velocities being what they are you must be able to accurately judge distance, or it will be real easy to wound the deer and not kill it. If you' re going to take 200 yrd shots practice, and practice out in the field where you don' t always know the range. You need to know where you are hitting at all ranges in which you plan to hunt.

You asked about sabots or roundballs. The Remington ML has a fast twist so it will handle sabots much better than roundballs. Second roundballs shed velocity pretty fast and are really a sub-100 yard projectile. Go with the sabots, a 240 gr. sabotted bullet will work great for you. If you' re inclined check out my site for some good info about getting starting in MLing.

Happy shooting
-Rkensparc