I was not happy with the flimsy polyethylene sabots available for BP and handgun use. The polyethylene ablated badly in the bore, and often separated or went nonconcentric prior to leaving the bore.
I had a local screw machine shop make some up out of MDS loaded Delrin (acetal).
The Delrin is much harder than the polyethylene, and the moly gives it great surface lubricity.
They did the body, and I cut them for separation with a single edged razor blade in a small arbor press.
I was able to achieve ungodly velocities out of standard .45 acp chambered weapons lofting 125 grain HP .357 bullets. The first batch were coming out of the barrel at very high speeds, up to 1800 fps.
I loaded some faster ones, but the first sabot out of the barrel with them sepatated and hit the chronograph, destroying it.
Doh! Good thing it was a borrowed chronograph...
Accuracy was combat adequate, but not bullseye match quality.