The "Accelerator" rounds came out a long time ago. Most of the shooters I know tried them and were as unhappy with them as I was. They produce groups like a shotgun - not like a rifle. Sabot rounds have very special requirements to be accurate. Those who own rifles with short, tight throats and slow rates of twist might be able to shoot sabot rounds but until the technology of sabots and the bullets they use catches up with the desire to shoot a very light weight sub-caliber bullet at hyper-sonic velocities I'll just stick to shooting the bullets that the rifle was designed to shoot at the velocities that actually meet the criteria of my uses.