What do we really know about the transonic zone?

[Distant Thunder]

The bullet I designed for my .40-65, 18-twist, follows that original Sharps design that I borrowed from the internet. It shoots very well to at least 600 yards and only weighs 382 grains. The design works very, very well. The OAL and length of the base diameter as well as diameters should be adjusted to fit the intended rifle and paper.