The .22 Long Rifle (.22LR) cartridge is widely used for target practice and small game hunting. While often considered quiet, understanding its actual sound levels is important for hearing safety.
The Sound of a .22LR
The sound produced by a .22LR firearm can reach significant decibel levels. From a rifle, it typically ranges from 140 to 150 decibels (dB). A .22LR pistol may generate even higher levels, sometimes approaching 157 dB due to its shorter barrel. These levels are comparable to a jet taking off or a .357 Magnum gunshot.
Ammunition type significantly influences the noise. Standard velocity .22LR rounds generally produce around 140 dB. Subsonic ammunition, traveling slower than the speed of sound, is quieter at 120 to 135 dB. Supersonic rounds exceed the speed of sound, creating a distinct “sonic crack” that increases overall noise to between 145 and 155 dB.
Understanding Decibels and Hearing Safety
Decibels measure sound intensity on a logarithmic scale, meaning that a small increase in decibel numbers represents a large increase in sound energy. For instance, a 10 dB increase signifies a tenfold increase in sound power. Sounds above 85 dB can cause hearing damage over time.
For impulse noise, such as from a firearm, the threshold for immediate and permanent hearing damage is often cited around 140 dB. Repeated exposure to noise at or above this level poses a significant risk. This can lead to tinnitus, a persistent ringing in the ears, and permanent sensorineural hearing loss.
Factors Influencing .22LR Sound Levels
Several factors contribute to the varying sound levels of a .22LR firearm. Ammunition type plays a significant role.
Barrel length also affects the sound. Longer barrels allow more of the gunpowder gases to expand and dissipate before the bullet exits, which can slightly reduce the muzzle blast. Conversely, shorter barrels, such as those found on pistols, generally result in a sharper and louder report. The use of a suppressor, often called a silencer, can substantially reduce the noise by cooling and slowing the escaping gases. While suppressors do not eliminate sound entirely, they can lower the decibel level of a .22LR by approximately 20 to 35 dB, potentially bringing it down to a range of 110 to 120 dB with subsonic ammunition.
Choosing and Using Hearing Protection
Using appropriate hearing protection is necessary given the .22LR’s sound levels. Continuous exposure to even seemingly lower decibel levels can result in cumulative hearing damage over time. Various types of hearing protection are available, each offering different levels of noise reduction.
Earplugs, which fit inside the ear canal, and earmuffs, which cover the entire outer ear, are common choices. Both come with a Noise Reduction Rating (NRR), indicating their effectiveness. Electronic hearing protection amplifies ambient sounds while blocking harmful impulse noises, allowing for better situational awareness. Selecting protection with an NRR sufficient for firearm noise is important. Proper insertion of earplugs and a snug fit for earmuffs are required to achieve the advertised noise reduction.