Live tests by independent reviewers of numerous commercially available suppressors find that even low caliber unsuppressed .22 LR handguns produce gunshots over 160 decibels.[14] In testing, most of the suppressors reduced the volume to between 130 and 145 dB, with the quietest suppressors metering at 117 dB. The actual suppression of sound ranged from 14.3 to 43 dB, with most data points around the 30 dB mark. A notable example is the De Lisle carbine, a British World War II suppressed rifle used in small numbers by Special Forces. This was recorded at 85.5 dB in official firing tests.[15]
Comparatively, ear protection commonly used while shooting provides 18 to 32 dB of sound reduction at the ear.[16] Further, chainsaws, rock concerts, rocket engines, pneumatic drills, small firecrackers, and ambulance sirens are rated at 100 to 140 dB.[17]
While some consider the noise reduction of a suppressor significant enough to permit safe shooting without hearing protection ("hearing safe"), noise-induced hearing loss may occur at 85 time-weighted-average decibels or above if exposed for a prolonged period,[18] and suppressed gunshots regularly meter above 130 dB. However, the US Occupational Safety and Health Administration uses 140 dB as the "safety cutoff" for impulsive noise, which has led most US manufacturers to advertise sub-140 dB suppressors as "hearing safe." It should be noted that current OSHA standards would allow no more than sub single second exposure to impact noise over 130 dB per 24 hours. That would equate to a single .308 round fired through a very efficient can. This result effectively requires all users of suppressors to wear additional ear hearing protection.
