I remember reading that they had figured out the wear solution.
And yes, the P90 doesn't have a rotary bolt, but it reused the vertical magazine idea of the G11, as I said.
Here is a neat movie of the P90 in action. It loads very slowly, so right click
here, choose "save target as..." then save it to your desktop. After it downloads, you can play it with Quicktime. There are some cool shots of the translucent magazine emptying out under full auto fire.