As far as lubing yes you should. I've heard of a few people who don't but most of us do. As far as sizing, it depends on you mold. If you had a mold made up for you to your specs for your bore size, then you can get away from sizing them. Of the .451 and .452 sizing dies that I purchased from lee, they sized my bullets to .450.5 and 451.5. For most shooters they find if the bullets are slightly oversized for their bore they will obtain better accuracy. For example, for my White .451 rifles they like the bullets to be sized to .451.5. This helps to seal the gasses behind the bullet, plus it helps to insure the bullet does not move off the charge while walking around while hunting.

Ed