When Remington came out with the Accelerator, they had to seal the "bullet" into the case using electric induction because that was the only way they could get enough resistance to burn the powder. They didn't give bad groups, but never as good as the original caliber, I got 5" groups out of a .30-'06 that would shoot under an inch with good regular ammo. Later, I tried some of those commercial sabots and for whatever reason could never get any kind of groups. I suspect that the problem was the one Remington found, but can't be sure of that. Of course, the gunzines had no problem hitting field mice at 5 miles, but then they could always shoot better than I can, at least in print.
Jim