On the .458-.459" bullet issue, I'd just go with .459" and not worry about it.
Having them "slightly" larger in soft alloy isn't going to hurt (or really affect) anything.
Better slightly larger than smaller.
When you think about it there such a small difference in these two dimensions.
Realize that we're talking DIAMETER here, which means 1/2 of that dimension on each side of the radius.
Which will be .0005" (which reads 5 Ten Thousandths)
Now consider a typical human hair's diameter is .003" (3 Thousandths).
Any questions?