I'm no expert here but I did sleep at a Holiday Inn last night. Not really. F class is relativly new form of long range ( 600-1,000) yard, slow fire, prone with rest, any rifle (up to .33 cal.) any sight competition. It was brought about by an older high power shooter who found that the normal course was becoming too much for him to do any more, but he still wanted to shoot along side his buddies and other competitors.
My son and I shot our first match last weekend (60x600), neither of us had shot more than 300 yds before. We had a blast and did pretty well also.
Hope this helps.
DD