Hello,
I am the proud owner of an IWC Portugieser Automatic 5007 since 2013 and I started interesting myself into the accuracy of those mechanical watches. I measured my timepiece using the free website Toolwatch.io and got +5.2 sec per day as a result.
I think that the precision is great but I wanted to know if any other owner had an even better precision that my own.
Cheers,
Alfred