content: They didn't. Anon is a faggot as usual. One who has never fired a gun in his life. The issue with muzzle flash, is that it is dependent on weather and lighting conditions, and even then, it's not always guaranteed that any given round will produce a visible muzzle flash. Anon is too fucking stupid to understand that combustion will always produce light and heat, even if it isn't visible to the human eye under all conditions. He's also too fucking stupid to understand how guns work with things like blow back and burning powder. https://www.youtube.com/watch?v=IwTUhqbxuJw  https://www.youtube.com/watch?v=6ptqNMGg948  https://www.youtube.com/watch?v=u6e6enPhs-A