Mark - I have driven the 410 Great Plains bullets to 1702 with 120 grains of FFg T7, and gotten good groups. Recoil is stout, though. But without the sub-base, can't keep them in a group the size of this computer screen. My understanding is that these plastic "wads" were designed for use in the Savage ML with smokeless powder - insulates the bullet from the heat/pressure. And they aren't very expensive. Roskoe.