Add to this the first rule of armed combat, "If the enemy is in range, so are you." (if you have equivalent weapons)
Also, "If the enemy has more capable weapons than you, them being out of range doesn't mean you're safe." example, You have a 5.56 assault rifle, the enemy has a .300 Winchester Magnum sniper rifle and is 1000m away. You stand no hope of hitting them but you're toast.