some of the youtube videos I went to to check out either tutorials on gunfire and muzzle flashes, as well as the videos I slowed right down to view them frame by frame.
This one is brilliant as it gives you a view of a few different guns firing, and shows you well their speed. it also shows realistic muzzle flashes at day time, which is to say none.
This next one gives you good info on the guns and their fire rate, which I found useful for trying to put these in as effects.
I also watched some movies action, such as Battle LA, The Boondock saints, and Fury to name a few. whilst I say watched, I was mostly slowing down the action and firing scenes and then skipping to the next ones to see how they had done it.