Here is an informal survey I made off of ISSF tv and the web

Air Pistols Used:
Jong-Oh Jin (KOR) - Steyr
Bin Zhang (CHN) - Morini
Brian Beeman (USA) - Steyr
Norayr Baktamyan (ARM) - Steyr
Damir Mikec (SRB) - Walther
Daryl Szarenski (USA) - Steyr
Franck Dumoulin (FRA) - Pardini
Walter Lapeyre (FRA) - Morini
Vladimir Isakov (RUS) - Walther
Mauro Badaracchi (ITA) - Morini
Lip Meng Poh (SIN) - Steyr
Julio Almeida (BRA) - Walther
Wei Pang (CHN) - Steyr
Tian Zhang (CHN) - Steyr
Yifu Wang (CHN) - Steyr
Rashid Yunusmetov (KAZ) - Steyr

There must be something fundamental about these guns!?