Thanks for all the advice.
I figure I'll try to hone out the sizer about 2 thousandths or so, and drop the sizer in a chunk of forged high-carbon steel I got off an old computer server rack and hammer the bullets through. Who knows, maybe I can take a chunk of high carbon steel about 4"x4"x4", have it machined with 10 .453 diameter holes and ram them home with the log splitter.
It's a sizer of galactic proportions. Maybe when I run out of bullets I'll resize a rockchucker.