Starting a New FAQ on silencers... Compiling notes...

[Quarterbore]

From: http://www-2.cs.cmu.edu/afs/cs.cmu.e...st/nfa_faq.txt

FIREARM SILENCERS

While the statute calls these devices "silencers" or "mufflers",
the US NFA industry term is "sound suppressor", as the word
silencer has been given a negative connotation, and because it is
inaccurate, as these devices do not eliminate all sound from firing
a gun. However you can point the folks who get all high and mighty
about the use of the word "silencer" to this definition; it is the
legal term.

18 U.S.C. sec. 921(a)(24) "The term 'firearm silencer' or
'firearm muffler' means any device for silencing, muffling, or
diminishing the report of a portable firearm, including any
combination of parts, designed or redesigned, and intended for
use in assembling or fabricating a firearm silencer or firearm
muffler, and any part intended only for use in such assembly or
fabrication."

As can be seen this covers improvised sound suppressors, and
component parts of a sound suppressor. There is no thresh hold
level of sound reduction for something to fall under this
definition. ATF used to require the device "appreciably" lower the
sound (see Revenue Ruling 57-38) In general recoil compensators and
flash hiders do not fall under this definition, but some designs
could fall into the category. As with any borderline device the
thing to do is to get a written opinion from the Technology Branch
of ATF.

Note that the silencer definition applies only to devices for
firearms, i.e. powered by an "explosive". An air gun silencer is
not covered. But if it can be used on a firearm it would be. Thus
an airgun silencer permanently attached to the airgun, or too
flimsy to be used on a firearm, should be exempt. If you have an
interest in pursuing this line of thought submit a sample or
drawings to ATF Tech. Branch. I am not aware of any airgun
silencer currently made, or determined to be exempt from this
definition. But clearly there is room under the definition for
such a gadget. Likewise, since antique guns, as defined in the
GCA, are not "firearms", a silencer for such a gun is not, or
should not be, covered. Perhaps one fitted permanently to a
pre-1899 gun? (SEE BELOW)

From http://www-2.cs.cmu.edu/afs/cs/user/...f_letter69.txt

DEPARTMENT OF THE TREASURY
BUREAU OF ALCOHOL, TOBACCO AND FIREARMS
WASHINGTON, DC 20226

??? 1999

903050:CHB
3311

Dear :

This refers to your letter of February 8, 1999, in which you asked
about permanently attaching a silencer to the barrel of an antique
firearm.

In our opinion, a firearm silencer or muffler, which is permanently
attached to the barrel of an antique firearm, would still be a
firearm silencer or muffler subject to the provisions of Title 18,
United States Code (U.S.C.), Chapter 44 and Title 26 U.S.C. Chapter
53, the National Firearms Act.

We trust that the foregoing has been responsive to your inquiry.
If you have further questions concerning this matter, please
contact us.


Sincerely yours,

[signed]
Edward M. Owen, Jr.
Chief, Firearms Technology Branch