Its the design of the nose that makes the difference. The Maxiball and Great Plains are more of a wad cutter design rather than a rounded nose design. The great thing about a wad cutter design is it acts like a cookie cutter and generally cuts a near perfect hole in the target instead of expanding and tearing a hole through the target. The Powerbelt is only .001 under bore size and an over bore conical is usually not over .510 so seeing a .010 to .011 difference in the hole would be difficult if they were both of the same nose geometry.