https://www.youtube.com/watch?v=9ZEG_BuvzQ4&feature=youtu.be
Every time when I shoot my fps drop down to 5-6 FPS.
Every time when I shoot in scope mode (LPRS ACOG DMS AMS and other) or in eye zoom mode my FPS drop down about 10-15 FPS.
10-12 FPS drop when look at smoke from smoke granade

• no fps drop when shooting with scope zoomed right at my player feet. -NO FPS DROP WHEN EQUIP SUPPRESSOR Small weapon cause small fps drop.

for ex
Vermin-8FPS
SPMG 15-FPS

FPS drop due to muzzle flash effect when shooting. especially in zoom or scope mode
Video show this bug