Nope, just sighting the scope and pulling the trigger. All of a sudden it just started making a whirring sound, like the motor/geartrain was spinning without any load on it. There was no snap, bang, or grinding like you would expect with a catastrophic failure, it just stopped shooting BB's...although they DID start rolling/drippling out the barrel
Based on that, I assumed the piston stripped, but the tappet plate was intact. I intend to take it apart this weekend, and share my findings.