I bought some of the sabots from J&D components out of Utah, about 20 years ago. I mess with them every once in awhile for something to do. So far the best results have come in the 30-30,I think mostly due to matching the bullet with the twist.
I never could get a "group" from the 30-06 they would string verticaly about 8 inches at 100 yds.
The 308's show a little tendancy to maybe get along with them, maybe with some serious sitdown loadwork up something would work out.
The best I got out the 30-30 would be a halfway decent varmint round, could get down to around 2 inches at 100, and when using the Winchester bulk 46 gr hp bullets, I wouldn't hestitate to load a magazine full.
Treat them much the same as loading cast bullets, flaring the case, varying crimps,seating depths etc.