I'm asking this question on behalf of a recent MRO / FAA repair facility that called me.
They're setting up a small peening machine with glass bead as the media. They've contacted a few distributors and was told that finding glass bead that meets AMS-2431/6 is difficult and other MRO facilities in the region use MIL-PRF-9954D glass bead as an acceptable substitute.
Does anyone have any knowledge/thoughts on this?