This guy knows how to film a gun being fired:
Make sure to check out his YouTube channel. He’s got several more videos, and they are all as good of quality.
I’m guessing he’s recording sound separately because the quality of it is damn good as well.
If you don’t watch the vids in 1080p with your system cranked to 11 you are doing yourself a disservice.
Even his mag changes are Operator as &@#* (for the most part.. bit of a fumble after that surefire one).