Keeping a scope cover on your objective and being aware of your flash is extremely important.  I highly recommend a flash kill cover for any combat optics and also suggest a cover for your flashlight.  Even something like a red lense will help avoid giving away too much reflection.   Flashlights are probable the biggest giveaway in low light even if you don’t turn them on.   Next time your at the range, put your rifle on the bench and walk down range and look again.   Keep in mind that even though you may be 50-100yds away and wearing camoflauge, your fancy schmancy M4 has various points of reflection and even moonlight will have an impact.

One trend that I haven’t jumped on the bandwagon with is the all of the battery operatored doodads on a rifle.    There are defintely reasons for putting lights on a gun and for 40mm objective lenses optics on your rifle, but many of those will stick out like a lighthouse in the field.   I remember a clear safety violation of a gun operator who was handling his rifle during a cease fire.   I was downrange about 500yds and turned and saw the flash of his Trijicon ACOG at that distance.   I knew he was handling his rifle, but it was too far for me to scream back and tell him to put his gun down.   It dawned on me that if I was the enemy, that guy would have been outed from 500yds away just because of how much his optics refected light.  He was actually  in the shadow of building and not in direct sunligh, nor was the sun shining from my direction on him.