The F-22 is equipped with the M61A2 20mm cannon. That would have been a damn sight cheaper than using the AIM rocket.
The 20mm cannon ejects brass shell casings. That and the projectiles will eventually fall back to Earth, somewhere...
I think most modern fighters capture their spent casings. I believe the ammunition self-destructs after a certain distance as well.
According to the reports I saw, they were already over the ocean. Which means they don't plan on recovering it.
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