I want to enjoy some of the upcoming spring weather by
casting some bullets. But the more reading I do,
the more questions I have.

One that I want to make is a 600grain bullet for the S&W 500.
And once I get that down, I will make some for my
44 magnum.

And, I'm looking at Mountain Molds for a mold.

Since a S&W 500 has a bore diameter of 0.500, and the
Mountain molds shoot for between 0.501-0.503.....

Do these bullets need to be resized, or is that acceptable?

If gas checks were necessary, resizing would be logical.
But some experts say gas checks are used to cover up
other existing problems, and shouldn't be necessary.

So my goal is to avoid the need for gas checks, and hence
not resize if I don't really need to.

What do you think?

Thanks,

Dave

Dave-

If your bullets drop from the mould of a correct diameter - you'll not need to size them.

Ideally - you'd like them to be at the maximum diameter that will allow loaded rounds to "just" chamber (.0005" under throat diameter is the oft quoted target). This larger dia will prevent leading problems and will also help keep the bullet in alignment with the bore to aid accuracy. The problem is the tolerance for the mould maker. Because of those tolerances - it is better to err on the too large side and minimally size the bullets than on the too small side which can lead to the problems with leading and poor pre-shot alignment.

Bullets without GC when cast well and at reasonable velocities work fine, cost less, and eliminate steps and potential variables.

Best regards-

Sky C.