Old Jim,
Nothing wrong at all water quenching those WW Bullets, unless you're against having a harder, more rounded bullet that will speed up your casting production

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Water quenching will up your BHN to about 19-21, depending on factors such as alloy and mold temp., and the WW alloy itself (antimony content), as this can vary slightly from different WW manufacturers. Bullets cast from WW, without water quenching, are usually 10-12 BHN. Harder bullets can be driven faster without leading your barrel. This is alot easier and faster than oven heat treating your bullets.
Your bullets will be rounder as they solidify instantly as they hit the water, rather than dropping from the mold onto whatever surface you choose, to cool.( when casting large bullets, I float a sponge on the water surface of my 5 gallon bucket, to slow the fall of the bullet from hitting the bucket bottom.)
Water quenched WW will maintain their hardness for approx. 6-12 months, before they age soften to about 17 BHN, where they will stay that hard almost indefinitely.
Lastly, your production will increase, as you can drop your bullets from the mold once the spru hardens, rather than waiting long enough to drop them, to prevent deformation.
So Old Jim, keep up the good work ! Water quenching your bullets has many beneficial benefits that you and your guns will enjoy.
Jeff