Ouch. Didn't realize that Metalgravy. Honestly, I only put 200 rounds thru mine, and that is no super test. If those crack also, I may try to carve some out of wood. Seems like the Sar would be a good candidate for aluminum, but there should be some kind of epoxy that wont crack. My first set, I tried supergluing back together, but it was still to brittle. Electrical tape held it together until I got the new grips.