Imagine your spouse, who will deliver a new baby in a matter of weeks, shakes you.

“I need some chocolate ice cream, dear. Will you go get me some?”

It’s 3 in the morning. You were sound asleep. You want to say no. You might want to say more, but you think before you speak. You turn on the light, stretch, pull on your pants and concealed carry pistol, give your spouse a kiss, and head out to the all-night convenience store. Sure, you grumble a bit, but you remember who’s doing the heavy lifting baby-wise.

The streets are deserted and you allow yourself to remain in the semi-fog of sleep until you’re pulling into the parking lot. The store is bright, but the lot is poorly lighted by a flickering mercury vapor overhead lamp. You get out of the car and, suddenly, you are face-to-face with a couple punks, one of whom shows a knife.

You back away and draw your pistol. He lunges. You fire once, twice and you realize you’re blinded by the muzzle flash. What happens next is up in the air, and you could live or die by the results.

At the Range

We go to the range regularly. It’s brightly lighted. We wear safety glasses and earmuffs. Sound baffles of various designs are installed on either side. We adjust the target distance, take a stance, raise our gun, take careful aim and squeeze.

At the local range or even at a training course, we might simulate holding with the Harries technique, a flashlight in an ice-pick grip, one hand beneath and bracing our dominant hand with the gun. We’re careful, thoughtful. We wait for commands like “range is clear” and beeps from little plastic boxes.

It’s a whole lot different in real life. In real life, an encounter takes place suddenly, unexpectedly. In real life, the muzzle blast, especially if you’re half-asleep, will be startling and the muzzle flash might be blinding. In real life, you won’t have a chance to use a hand-held flashlight. Cops use flashlights and train for low-light encounters, but a true self-defense situation from a private citizen’s point of view will rarely involve anything but a sidearm.

What is Muzzle Flash?

Muzzle flash is the visible and infrared light emitted when a cartridge fires, and it is generated by burning gunpowder mixing with oxygen. The size and shape of the muzzle flash, as well as its intensity, are dependent on several things: the type of ammunition or composition of the cartridge being fired; the characteristics of the firearm, such as length of the barrel, whether it is a revolver or pistol and the presence or absence of porting; and whether there are devices attached to the gun at the muzzle, such as a muzzle brake or flash suppressor.

Writing principally about naval weaponry, retired Electrical Design Engineer Tony DiGiulian at NavWeaps says that only about 30 percent of the chemical energy released from the propellant is converted into the useful kinetic energy of actually moving the projectile down the barrel. The rest is, in a sense, “trash energy” that is dissipated in the muzzle flash.

DiGiulian say there are five components to muzzle flash:

  1. Muzzle Glow — The tiny tongue of flame and unburned propellants that leak past the bullet and exit the muzzle before the bullet leaves the barrel. It persists until chamber pressure drops significantly as the heavy, inert bullet is separated from the case and pushed down the barrel. A cold gun (or a new gun with a lubricated barrel) will show less muzzle glow than a hot gun.
  2. Primary Flash — The propellant gases that exit the muzzle behind the projectile. These are hot enough to emit large amounts of visible radiation but cool rapidly as they expand away from the muzzle.
  3. Intermediate Flash — A reddish disc, slightly dished toward the gun, a few inches from the muzzle at the time the bullet leaves the barrel. It persists until chamber pressure drops. This is called a “Mach shock wave” and it is created by pressure from the escaping gas and bullet, which cause the escaping gas to heat and become “self-luminescent.”
  4. Secondary Flash — The ragged vortex of yellowish-white flame caused by the ignition of the turbulent, combustible mix of propellant gases and atmospheric oxygen caused by the turbulent mixing occurring at the boundary of the gas jet as it leaves the muzzle.
  5. Sparks — Common to all small arms, these are incompletely burned, residual powder particles.
Blast from a Remington R1911 muzzle flash

SHOWN HERE IS THE BLAST from a Remington R1911 in the “Secondary Flash” phase, or the phase of the muzzle flash comprised mostly of long tongues of flame.

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.

AS USUAL, DIFFERENT LOADS will yield different results, but generally speaking, the longer the barrel, the fewer sparks will be visible as the additional barrel length allows an extra microsecond or so for the powder to burn within the gun.

AS USUAL, DIFFERENT LOADS will yield different results, but generally speaking, the longer the barrel, the fewer sparks will be visible as the additional barrel length allows an extra microsecond or so for the powder to burn within the gun.

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.

Switching from a revolver to a semi-auto will most likely reduce muzzle flash.

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.

Eyes are complex mechanisms, not one-size-fits-all body elements. Eye components age or can become injured or stressed.

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