So What?

Muzzle flash is an issue for two reasons, both having to do with low-light shooting. First, muzzle flash can temporary blind you. If that happens, you might not know how many assailants you’re confronting, and presuming that you’ve identified all of them prior to having to take a shot is foolish and reckless. Additionally, in a close encounter, you might not be able to effectively defend yourself against blows or knife stabs or slashes. Second, in any defensive situation, muzzle flash can give away your position to a particularly cagey attacker.

Your Eyes and Self-Defense

If you’ve ever stuck a finger in your eye, you know just how painful that can be. That’s nature’s way of telling you — if you didn’t already know — that your eyes are incredibly sensitive. You might remember how the eye works from high school biology. According to the American Optometric Association:

1. Light rays reflect off an object and enter the eyes through the cornea (the transparent outer covering).
2. The cornea bends, or refracts, the rays through the round hole of the pupil.
3. The iris (the colored portion surrounding the pupil) adjusts, making the pupil bigger or smaller, regulating the amount of light admitted.
4. Light rays pass through the lens, which changes shape to further bend the rays and focus them on the retina.
5. The retina contains millions of light-sensing nerve cells, called “rods” and “cones.”
6. In the retina’s center, cones provide clear vision. They detect colors and fine details.
7. Outside the center, rods provide peripheral or side vision. They also detect motion and work in dim light and at night.
8. Rods and cones convert light into electrical impulses. The optic nerve sends these impulses to the brain, which produces an image.

It’s quite a miraculous chain of physiological events and works amazingly well … until someone pops a flash bulb in your face or you experience a bright muzzle flash at night. Then the normal functioning of rods and cones is disrupted. The optic nerve sends an undecipherable message to the brain, and the system goes wacko.

Why Wacko?

At basketball games, you are asked to take no flash photos because doing so could distract the players. Think about the UV-blocking visors that fighter pilots wear at extraordinarily bright high altitudes or the vermilion or school-bus-yellow goggles you wear when you snow ski. These are all warnings about and precautions against an optical condition called “flash blindness.”Flash blindness is a visual impairment of the rods and cones, what ophthalmologists call “bleaching,” during and following exposure to an intense flash of light. That intense flash could be muzzle flash or even a camera flash in the face. At night or in low-light situations, your dark-adapted pupil is open wide, so flash blindness has a greater effect and lasts longer, which is a problem. The effects might last for a few seconds or a few minutes and, in a self-defense situation, a few seconds can kill.Normally, ambient daylight is extremely bright and bombards your eyes through your entire 120-degree arc of vision. Most of that arc is peripheral vision and hence biologically designed for less clarity and resolution than in the center of your field of view, where there is a higher density of cone cells. The only time you experience a moment of flash blindness is when you pass, for example, from a poorly lighted space into a bright space. Think of walking along a tunnel in a pro football stadium and then emerging into the open at noon to find your seat. You blink and close your eyes for a moment; then you squint, shade your eyes and allow your pupils to adjust to the change in light intensity. You have just experienced retinal bleaching, and you might throw on sunglasses or a ballcap to shade your eyes.Contrast this with a bright muzzle flash. You’re quickly concentrating on the front sight and the flash occurs right in front of your cone cells; right in front of the part of the eye that is most crucial for vision and for understanding your fighting environment.

Combating Flash Blindness

Unless the flash blindness you’re experiencing is caused by the flash of a nuclear warhead, sustained exposure to an arc welder or from staring directly into the sun, your eyes will soon adjust. That said, it’s within that “soon” time period that a person experiencing temporary blindness from muzzle flash can die. So what can realistically be done other than refusing to go outside in the evening?A longer barrel gives powder in the cartridge longer to burn and, generally speaking, the longer the barrel with the same load, the faster the bullet. It’s barely a microsecond, but it makes a difference in reduced muzzle flash. And porting the barrel, while it might reduce muzzle rise, will direct a portion of the flash upward into your field of vision. In a close-range encounter, with a gun held closer to your body than at the shooting range, this might not be a problem.Switching from a revolver to a semi-auto will most likely reduce muzzle flash. A semi-auto certainly has muzzle flash, but a revolver also leaks between the barrel’s forcing cone, which is fixed in the frame, and the cylinder that houses the cartridges. A variety of colored ballistic lenses (polycarbonate) are available to change the shading of ambient light and targets. Many shotgunners prefer a lens that heightens the contrast between an orange flying disc and the target background. Depending upon your personal sensitivity to light, amber lenses block blue light and work well on low-light or cloudy days.Mechanical devices can help suppress muzzle flash by interfering with the shock wave, but they could require a threaded barrel or the services of a gunsmith. Anything attached to your handgun, be it a laser, a flashlight or a scope, makes the gun less manageable to holster or draw and maneuver, and not all muzzle devices are the same:

• A flash hider mixes air and unburned powder at the end of the muzzle to minimize the flash.
• A compensator counteracts muzzle flip by venting some of the gas vertically.
• A muzzle brake reduces recoil by directing gas against a metal barrier before venting, which pushes the gun forward and counteracts some of the rearward force of the shot.

Search for low-flash, clean-burning ammunition, perhaps a specific “self-defense” ammo, for your sidearm and then take it to the range as late in the day as possible to compare it with other loads. Powders might not be infinitely variable, but the size and shape and composition of the grains can make a huge difference. Hand-loaders might have an advantage here since it is easier to vary ingredients of a standard load. And consider ramping up bullet weight, as a heavier projectile requires a more significant powder burn — greater energy — to force it out the barrel.Ophthalmologists tell their patients that everyone’s eyes are different. Eyes are complex mechanisms, not one-size-fits-all body elements. Eye components age or can become injured or stressed. Thus, muzzle flash might be a significant problem for you in low-light situations … or it might not. But why not find out sooner rather than later? See if you can find a way to shoot safely in the dark, because later could be too late.

Sources

NavWeaps: NavWeaps.com
American Optometric Association: AoA.org