September 23, 2010
Tips on ear protection for shooters.
When I was growing up, no one warned me about the hazard of hearing loss caused by shooting firearms. It wasn't because grownups were being neglectful; it was simply due to the fact that the entire shooting world seemed to be totally ignorant on the subject. And this included institutions like the United States military where it was not uncommon for an officer to ridicule a green recruit who placed wads of cotton into his ears to protect himself from rifle or even artillery fire.
For maximum hearing protection when shooting clay targets, the author always wears foam ear plugs beneath muffs; shooting from inside a partial enclosure as seen here at a sporting clays station section can increase the noise intensity of a firearm at the shooter's ears.
My hearing began to deteriorate at an early age and like most shooters in those days I was unaware of what was taking place. I received my first shotgun and .22 rifle at the age of 12 and while I was only allowed to use them under my father's close supervision, ammunition was cheap and small game was plentiful in those days so I shot both a great deal.
But the serious damage began a few years later after I bought a Ruger single-action revolver in .357 Magnum. I was set up to reload the cartridge and that along with a huge supply a lead from which I could cast free bullets encouraged me to shoot the revolver a lot. And, of course, I wore no ear protection while doing so.
I know now that the ringing in my ears after each shooting session is called tinnitus and it was an indication of permanent hearing damage but since it always eventually went away, I ignored it. And then one day the ringing did not go away and it has been a constant reminder of something that could have been prevented only if I had been told how to do so.
Like most long-time shooters who are plagued by tinnitus, I have learned to cope with it, but I'll have to admit that life today would be a bit more pleasant had I known back then what I know now about how the human ear works and how it can be protected from damage.
The way our hearing works is far more complex than I can cover in this column but here it is in a nutshell. When sound waves enter the outer ear and travel through the ear canal, they cause the eardrum to vibrate and those vibrations are transmitted to three tiny bones within the middle ear.
Those bones amplify the sound vibrations before sending them on to the inner ear (or cochlea) which is shaped like a snail and filled with fluid. A membrane called the basilar divides the cochlea into upper and lower sections and when struck by vibrations, its interior begins to ripple. Those tiny waves cause hair cells riding atop the membrane to move up and down into contact with another membrane, causing it to tilt to one side.
The tilting causes microscopic pores in the surfaces of the hair cells to accept certain chemicals, thereby creating an electrical signal. The auditory nerve carries this signal to the brain which translates it into a recognizable sound. Higher-pitched sounds are detected by hair cells located near the base of the cochlea while those further out detect lower-pitched sounds.
The custom-formed ear plugs worn by shotgunning sensation Kim Rhode as she instructs another shooter are the most comfortable type of ear protection available.
The intensity of sound is expressed in a logarithmic unit of measurement called a decibel (dB). The more intense (or louder) the sound, the higher the dB. Noise-induced hearing loss (NHL) occurs when the cochlea of the ear is subjected to dB levels high enough to damage its hair cells. It can be caused by a one-time exposure to an impulse noise such as an explosion or by exposure to the continuous loud noise like that produced by a chain saw.
According to the Occupational Safety and Health Administration the human ear can withstand a continuous noise level of 90 dB for eight hours in a factory without damage but for only 15 minutes at a level of 115 dB. According to military and industry standards, exposure to an impulse noise level higher than 140 decibels will damage the ear with only momentary exposure while the American National Standards Institute puts the recommended maximum at 130 dB.
Most firearms produce similar levels of impulse noise when fired so regardless of whether you are shooting a 12-gauge shotgun, a .357 Magnum revolver or a rifle in .30-06, your ears are subjected to noise levels in the 175 dB range. However, those levels are measured at the muzzle of a firearm where the noise is highest and it can be considerably lower at the ear.
Not long back I read the results of tests performed on a shooter who was firing a rifle in .22-250 and while the sound level meter being used indicated a noise level of 150 dB at the muzzle of the rifle, it was 112 dB near the shooter's ear. This may not sound like much but since decibels are based on a logarithmic scale, an increase of only three dB results in doubling of intensity.
Other factors influence how hard your ears get hammered by a firearm. A short-barreled shotgun does not actually generate more noise than one with a longer barrel but since it positions muzzle blast closer to your ears, the dB level they are exposed to is increased.
Same goes for shooting in an enclosed area such as an indoor pistol range or from one of the partial enclosures sometimes seen at certain stations on sporting clays courses.
By lengthening sound reverberation time, an enclosure can increase the sound impulse duration by three times or more compared to shooting in an unenclosed area. And like I said before, the longer the ears are exposed to excessive noise the greater the damage. As a rule, a right-handed shooter suffers greater hearing loss in the left ear than in the right and it is just the opposite for a left-handed shooter.
The best way to avoid hearing loss caused by exposure to firearms is to avoid them entirely but since doing so would make life far less enjoyable for most of us, wearing something that reduces the level of noise reaching our ears to a safe level is the thing to do. Hearing protection comes in two basic forms, plugs that go into the ear canal and muffs that cover the entire ear.
Ear plugs are the most popular mainly because they are inexpensive and many shooters find them to be more comfortable to wear than muffs (especially during hot weather).
They range in cost from throwaway plugs made of memory foam to more expensive plugs that are custom-molded to the ear canals of the individual shooter. The latter comes in kit form consisting of two putty-like materials. When mixed together as per the included directions and placed into the ear canal and left there for a few minutes, the mix solidifies to a rubber-like consistency.
The expandable foam ear plugs the author wears while hunting can be used only a few times before they begin to lose their effectiveness in reducing noise.
When both types of plugs are installed in the ear properly, the noise reduction rating (NRR) of the inexpensive foam variety and the more pricey custom-molded plugs is the same but some shooters find the latter to be more comfortable for extended use. Foam plugs are intended for one-time use but they can usually be used a couple of times before they begin to lose their sound attenuating capability.
The two basic types of muff-style ear protectors are standard and noise-activated, the latter battery operated. The noise reduction ratings of the two are the same but many shooters prefer the electronic muff because it allows its wearer to hear continuous sounds such as normal conversation while electronically reducing impulse noise to a safe level.
Ear plugs and muffs are usually rated about the same in noise reduction effectiveness, but when the muff is worn properly, it may have a slight edge. I say this because some of the noise that reaches the inner ear passes through the flesh and bone of the skull rather than through the ear canal and the muff covers a great deal of the surface area around the ear.
The design of muff makes it effective in noise reduction but only when its inner cushions fit snugly enough against the wearer's head for a proper seal. Long hair between the muff and the head can allow noise to leak in and the same goes for wearing eyeglasses with temples thick enough to interrupt the seal. This is why the temples of good shooting glasses are made of thin wire rather than thick plastic.
Before closing I must mention that the noise reduction ratings given to both ear plugs and ear muffs by their manufacturers are often based on their attenuation of continuous noise (such as in a factory) and may not be a true indication of the protection they offer from impulsive noise such as a firearm. While either ear plugs or ear muffs alone seem capable of reducing excessive noise to a safe level, I think using both is a wise thing to do, especially during prolonged shooting.
I use ear plugs alone when hunting but when shooting one of the clay target games I make it a point to wear both. Opinions among experts differ on the benefits of using double ear protection but I am sold on the idea when a lot of shooting in a short time is involved. Regardess of whether the additional protection is big or small, it may be just enough to keep me away from the hearing aid store a bit longer.