60 gr 3f will be quite suitable for any deer within average smoothbore range if you can lay balls atop one another at 100 yds you might want to go to 80 gr IMHO, I would let the gun show me what gives the best accuracy at 50 yds and add this to the decision, I used from 70-90 gr 3f in several .62 smoothbores as each gun had a load itbliked the best and I felt all were good fro my 50 yds max, I do not concern myself for that infamous Deer of a lifetime as it may always be just beyound you comfort level no matter what gun you carry is really a non issue, if you use a sharps dialed in at 1000 yds max shot effectiveness / poa certainty your once in a lifetime Deer will probably pop up at 1200 yds, you may find that a bit more than 50 grains may flatten out the trajectory and while not needesd to kill efficiently will make aiming and hitting a target much easier, with no hold over or under do some testing and listen to your gun more than to our experiences as smoothies are a funny breed in what they like or don't like