I get the freeze when I fire my guns on a con first time .
UPDATE :First time I hit a plane with gunes frame rate went from a peged 60 to 49 with small freeze inbetween .
Like Lusche says , it seems to be when I hit a plane as I havn't tried a building yet so far .
I just checked , on this new pc I hadn't had the sound turned down to standard yet ( me bad sorry

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Will check that out soon as I can see if that made any differance .
Busy day here Easter and all

UPDATE : It helped some , FR only went from 60maxed to 53 now , with a smaller stutter than before . Just to say
it has no stutter or FPS loss on the second drone I just shot down offline .
I also fired my guns prior to shooting the first one down so it seems "to me" that it's just the plane exploding , seems it's not the guns themselves like I first thought playing the game online .