Are these professional flooring contractors? If so, they're idiots and cheating their clients
. It is OK to use an air finish gun to face nail and toe nail when starting and ending a room of hardwood but to nail the entire 3/4" floor that way is WRONG. I suppose it could work but nobody does it that way on purpose; unless they're to cheap to rent/but the right tools. 3/4" solid T&G floors are meant to be nailed with staples or cleats. Yeah, 75 years ago they were hand nailed and had problems then and still do. Can you say SQUEEK? Today, and for the last fifty years, they are machine driven, cleats or staples, air or manuel.