I’m pretty sure that any such microstamping law would have a provision making it illegal to buy a firing pin unless you went through a process to re-register the handgun with appropriate stamp. I imagine also that reloading would be illegal (most politicians are unaware of reloading, though) since the reloaded shell casing would already have a stamp on it.
The goal of this is to stop sales of handguns to the good people. Lefties don’t care at all about theft, robbery, street crime, and all the rest unless it can be used to advance the left.
Only the spent primer would have the stamp on it. It’s easy to pop those out and dispose of. If I were a bad guy, I’d just go to a range and collect a bunch of empty casings and toss them around the crime scene.
So far as I know, the stamp would, by definition, hit the primer since it is engraved on the firing pin. Thus, since the spent primer is removed as part of the reloading process, the case is just fine for reloading and further use.
This is one of the most idiotic, although persistent, ideas out of the clown show.