AA already comes with a "relief cut" and still gouges the heck out of the receiver.
This is after only 300 rounds. It has slowed/ceased since that, but still hard to look at.
The more I learn about piston AR's, the less I'm impressed with them (and have since added a DI to the stable). No matter how you slice it, a piston AR will place ALL of the recoil force on the front lugs of the barrel extension. A DI PUSHES the bolt forward. As the pressure is still FORWARD on the bolt, with the BCG starting to move backward, THEN it unlocks/turns the bolt (which is why DI's get minimal wear there). However, a piston AR just slams back (no forward pressure on the bolt, and yes, an AA bolt spring is useless as it's nowhere near the pressure of DI's gas) and rips the bolt back, causing it to twist to clear the barrel lugs and then slamming the cam pin into the cutout edge to finish aligning (completing twist) the bolt. The parts may have proven to be able to handle this, but it's NOT a proper way for a rifle action to operate. It took me a while to understand, but now I understand why people say "if you want a piston setup, get one that's been DESIGNED as one from the start". "Conversions systems" may work, but I no longer would trust my life to one.