Depending on the lead alloy and the type of mold, the bullets may not cast the perfect size.
Pure lead will shrink a little which is okay, especially for muzzle loader molds.
Molds for modern bullets are made to use with a lead alloy, if the alloy is harder then they may end up a little large, you never know unless you try.
Why not try some .451 or .452 lead bullets of a similar weight and see how they shoot first?
There's also .429 - .430 lead bullets that are just about the same weight
They may even have a better sectional density.
Sometimes the type of sabots and powder make more of a difference than the bullets.
Other times the bullets just won;t shoot straight no matter what you do.
I do prefer sabots because they don't wear out the rifling at all compared to bore size bullets, unless you have a nitride coated bore.
Last edited by arcticap; 05-15-2019 at 07:58 AM.