Okay, I beat my last distance record (to Rio) running QRP. Though this time it was actually at five watts: 6058 miles to Tandil City in Argentina on the 10m band. Very nice.
Technically speaking, the 2.5 watt contact to Rio was better efficiency for watts per mile. But for the raw distance factor, I’m pleased with this contact to Argentina and on 10m no less. That’s a relatively rarely-used band in my part of the world.