Are you talking about the sabots with a .223 55 grain bullet? I know Remington used to load those in the 30-06, and probably the 308, I'm not sure. They called them the "Accelerators." As far as I know they don't make them anymore, but I could be wrong. They were meant to turn a big game rifle into a long range varmint rifle. But the reports I heard on their accuracy were generally not good. If these are what you are asking about, what do you intend to use them for? I hope not deer or elk?