I believe a guy on modernmuzzleloading.com has played around with this idea some. He was able to get good accuracy with a .358 180 grain rifle bullet using the .357/.45 PR bullet orange sabot. But only out of his 1 in 20" White rifle. I believe he tried with his 1 in 30" Knight inline and the bullets were keyholing.

I've thought of this idea as well, but it seems few people have had success with a 1 in 28" or 1 in 30" twist, so I just haven't bothered. The other thing, I'm not sure how well a rifle bullet will expand at muzzy velocities. That .358 bullet is designed for .35 Remington/Whelen velocities, so it might not open up at 1700 or 1800 fps....