I have two unopened new boxes of Handy SST .45 cal sabots plus an opened box with 17. The three I used flew sideways in a 1-48 twist Kentucky so you need one of those fast twist inline muzzleloaders.

$50 for the lot plus postage if I mail them. Weight will be between 2 and 3 pounds.

Although the fully assembled bullets are designed for .45, and do work in Kentucky, the bullets themselves are .40 cal and might be worth a try on a modern center fire reload. They are 200gr and have plastic tips which are supposed to really help with expansion. Just a thought for the experimenter.