Like his father, the younger Maxim was also an inventor of
note, with a number of designs and patents to his name, including the subject of today's post: the silencer. Perhaps I should call them suppressors, mufflers or moderators as these devices soften, but do not completely silence, the report of a gunshot. Regardless of the proper terminology, however, Hiram Percy Maxim called them silencers, creating the Maxim Silent Firearms Company in Hartford, Connecticut in 1908 while waiting for his patent to be approved. In 1912, he incorporated the business as the Maxim Silencer Company.
However, I'd prefer to focus on the technology itself. In patent number 916885, issued on March 30, 1909 and titled "Silent Firearm", Maxim described his invention as:
"A silencing device for
firearms, comprising a supporting shell or casing and a series of diaphragms or
spreaders disposed in said shell or casing and forming therein a succession of
chambers, each of such diaphragms or spreaders having an opening for the
passage of the projectile and for the escape of the gasses from each chamber
into the next and from the last into the atmosphere."
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Detail of Silencer from Maxim's Patent |
Allow me to rephrase this in modern English: after the
bullet passes through the suppressor, the propellant gasses are diverted by
these diaphragms and fill the chambers, both slowing and cooling said gasses,
until eventually they exit the suppressor, reducing the audible volume of the
shot by varying degrees.
Current terminology calls the diaphragms or spreaders
baffles and the chambers are called expansion chambers, and units with different shapes, numbers, and sizes of both chambers and baffles are regularly designed
in an attempt to reduce weight and improve efficiency. See the list at the bottom of this article for more information.
Early silencers had some notable differences from the
devices we're generally used to today. First, Maxim's original silencers were
designed with the bore axis off center from the tube, which meant the mass of
the silencer hung below the line of the barrel, allowing the use of factory
iron sights. With few exceptions, most modern suppressors are concentric to the
firearm bore and require either a raised optic, or special suppressor-height
iron sights.
The second difference is the internal arrangement of
expansion chambers. Maxim's silencers were designed to direct the escaping
gasses in a particular manner. In his own words:
"They [meaning the gasses] are
made to dissipate their energy by being given a rotary or whirling movement in
a suitable chamber, the velocity being so great that the gasses are held by
centrifugal action against the wall of the chamber until by friction against
such wall the velocity is gradually retarded and the gasses are permitted to escape
gradually through an opening."
This design, while effective, is more complicated and
therefore more expensive to produce. Simpler, but nearly as efficient
suppressors are available on the current market.
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Two of the author's auppressors |
One thing to keep in mind is that suppressors are not like what we hear in the movies or
on TV. They don't reduce the sound of a gunshot to a soft thud; it's still
clearly a gunshot, and it's generally uncomfortably loud at close range or
indoors. While suppressors can potentially reduce the noise of a gunshot by up
to 35 decibels, about as much as quality ear protection, the resulting volume
is still frequently above 130 decibels. According to OSHA, 140 decibels is the
danger level where immediate, permanent, hearing damage occurs.
The most efficient suppressors, on the smallest and quietest
caliber firearms, generally only reduce the sound of a gunshot to between 110
and 120 decibels. For comparison, fire engine and ambulance sirens are
generally in the 120 decibel range. The ability to suppress a firearm to truly
comfortable hearing safe levels is more of a challenge than most people
realize.
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Same suppressors mounted on different firearms |
With the development of additive machining and improved
materials technology, modern suppressors can be more efficient and lighter than
their predecessors. There are a number of suppressor companies offering a wide
variety of units in different calibers, styles, and price ranges.
The only
reason suppressors aren't more common and less expensive is legislative. Thanks to the National Firearms Act of 1934, those wishing
to purchase or construct a suppressor must first send an application to the
Bureau of Alcohol Tobacco Firearms and Explosives. This includes submitting
notarized forms, fingerprints, informing the chief law enforcement officer in
the applicant's jurisdiction, and a non-refundable $200 fee.
While wait times can vary considerably, eight to nine months
seems to be fairly common. My last suppressor application was submitted in
early December of last year, and was finally approved in early August of this
year, for a total of about 250 days.
Currently, private possession of suppressors is legal in 42 states. However, they may not always be legal in every municipality in those states. In addition, suppressors can be used for certain types of hunting in 41 states. For those interested in contributing to the fight for greater suppressor liberty, I highly recommend making a donation to the American Suppressor Association.
Whether they're called silencers or suppressors, mufflers or
moderators, these beneficial firearm accessories should be inexpensive and
readily available to all shooters. Hearing damage is cumulative and permanent
and will eventually affect us all.
Have fun, and safe (and quiet) shooting.
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