Gemtech SFN-57 Instruction Manual

TM-SFN-57
OPERATION AND MAINTENANCE
OF SOUND SUPPRESSOR
MODEL SFN-57 and SAR-57
Before using this suppressor,
be certain you have read and
understand this manual.
Manufactured by
GEMTECH
Div. of Gemini Technologies, Inc.
P.O. Box 140618
Boise, Idaho 83714
ISSUED: October 16, 2013

SOUNDSUPPRESSORMODELSFN-57™ (5.7mm) P. 2
ÕÕÕÕÕWARNING ÕÕÕÕÕ
"Because sound suppressed-weapons make less noise
than non-suppressed weapons, it is easy to forget that
they are still firearms. It is of vital importance to remem-
ber that a sound-suppressed firearm is just as dangerous
as a non-suppressed one, and the same safe handling
requirements apply.
TM-SFN57
FIRSTEDITION November2005
SECONDEDITION January2007
THIRDEDITION October2013
Published by:
ATI Star Press
Antares Technologies, Inc.
P.O. Box 140618
Boise,Idaho 83714
Phone:[phone]
TRADEMARKNOTICE:
SFN-57™isatrademarkofGeminiTechnologies, Inc.
Five-Seven™ is a trademarkof FNNH, SA
COPYRIGHTNOTICE:
©2007GeminiTechnologies, Inc.
All rights reserved. The contents of this publication may not be reproduced
in any form or by any means in whole or in part without the prior written
permissionofthecopyrightowner.

SOUNDSUPPRESSORMODELSFN-57™ (5.7mm) P. 3
TM-SFN-57
OPERATIONALMANUAL
FORSOUND SUPPRESSOR
MODELSFN-57 and SAR-57 (5.7mm)
Manufacturedby
GEMTECHDivisionof GeminiTechnologies,Inc.
P.O. Box 140618
Boise,Idaho 83714-0618
Phone:[phone]
FAX:[phone]
CONTENTS:
GeneralDescription........................................................................... P. 4
Physical Specifications ..................................................................... P. 5
AmmunitionNotes ............................................................................ P. 5
UseandOperation Instructions ......................................................... P. 5
Maintenanceand Cleaning ................................................................ P. 6
Warranty Statementand Repairpolicy .............................................. P. 7
IMPORTANT
The manufacturer disclaims any liability for damages resulting from
any unauthorized modification of this product. Any modification of
this suppressor without prior express authorization from Gemtech’s
Engineering Department will void all warranties, both written and
implied, and will result in the assumption of all liability by the person
performing the unauthorized modification.

SOUNDSUPPRESSORMODELSFN-57™ (5.7mm) P. 4
ÕÕÕÕÕWARNING ÕÕÕÕÕ
"Failure to follow installation and maintenance instruc-
tions detailed in this manual can result in potential for seri-
ous injury to the user and damage to the weapon. Beinguser-
attached muzzle devices, firearm sound suppressors are subject
to improper attachment unless the proper procedures outlined in
thismanualarefollowed.
MANUFACTURER’S DISCLAIMER
The manufacturer is not responsible for improper usage of this product.
This product is potentially dangerous, and as such it is the user’s re-
sponsibility to understand and implement its proper use. If you do not
understand the instructions in this manual, please contact the manufac-
turer for further clarification.
ÕÕÕÕÕWARNING ÕÕÕÕÕ
The SFN-57 suppressor has been designed to operate dry,
and introduction of any so-called “artificial environment” (wa-
ter, oils, greases, etc.) can cause dangerous internal pressures
with possible injury to the user and damage to the suppressor.
GENERAL INFORMATION
TheGemtechSFN-57 suppressor was designed specifically for the FN
Five-SevenpistolmanufacturedbyFNHerstal and distributed by FNH. The
suppressor features Gemtech’s high efficiency baffle stack and has been
specificallyoptimizedfor this weapon only and its 5.7 x 28mmammunition.
The SAR-57 differs only in that the rear mount is threaded 1/2-28 for
commonUSthreadedcarbineschamberedfor the 5.7x28mm cartridge.
Allmuzzleattachments,includingsuppressors, will change barrel har-
monicsandstanding waves. This resultsinaslightchange in point of impact
with the device in place. The SFN-57 suppressor will have no deleterious
effectongroup size.
This suppressor is effective in markedly reducing the sound of the
muzzleblast,makingitdifficultforanobservertodeterminethe origin of the
shot and eliminating the need for shooter hearing protection. There is no
way of eliminating the ballistic crack (or sonic boom) of the projectile travel-
ing downrange when using the standard SS-190 ball ammunition.
When using the SB-193 subsonic ammunition (white tip), the domi-
nant sound becomes that of the mechanical noise of the weapon and the
projectileimpactingthe target.

SOUNDSUPPRESSORMODELSFN-57™ (5.7mm) P. 5
Thissuppressorcontainsnoexpendablepartsand may be cleaned by
immersion in suitable solvents and oils. This instruction manual gives the
necessary instructions for maintenance of this unit.
OVERALL EFFECTIVENESS
The real limiting factor on the effectiveness of centerfire rifle suppres-
sors is related to the sound of the bullet in free flight. The free flight bullet
noiseis related to thegeneralbulletshape and is alsodirectlyproportionalto
the bullet velocity, and all the 5.7x28mm ammunition (except the SB-193
Subsonic)issupersonicwithsignificantbulletflightnoise.TheSFN-57 sup-
pressor is capable of reducing the sound of the muzzle blast to below the
level of bullet and action noise. Because of the sound level of the bullet in
flight, it is not possible to truly appreciate the degree of reduction when the
muzzle blast is reduced to less than the bullet flight noise unless subsonic
ammunition is used.
Besides sound suppression, there are other benefits of a sound sup-
pressorwhichareseldom mentioned. Sound suppressors are exceptionally
effectiveflashsuppressors. This is an important consideration when usedin
theflammableatmosphereoften encountered in drug labs.
SPECIFICATIONS
Length: 6 in.
Diameter: 1.25 in.
Weight: 5 oz.
Muzzlethreads M10x1(1/2-28 for the SAR-57)
Suppressionlevel: varies with ammunitionused
ConstructionMaterials Hightensilestrengthaluminum
AMMUNITION
At the time of printing of this manual, four types of 5.7 x 28 mm ammu-
nition are produced by FN for the P90 Personal Defense Weapon and the
Five-Sevenpistol. ThestandardSS-190 ballammunitionis supersonicandis
identified by a black tip. The practice ammunition has no markings on the
full-metal-jacketedprojectile.The SB-193 Subsonic ammunition isidentified
bywhitemarkingonthefull-metal-jacketprojectile.TheTracerammunition,
L191, is identified with a red marker. All three of these factory rounds are
certifiedforuse by FN in the P90andallaresuitable for use with the SFN-57
suppressor.
Gemtechspecifically cautions against theuseofnon-FNapproved am-
munition, and use of such ammunition will void both the warranty issued by
FN as well as the warranty for damage to the suppressor.
TheSFN-57 suppressor hasbeenspecificallydesigned for usewiththe
FN 5.7 x 28 mm cartridge. Use with any larger cartridge, such as the 5.56 x

SOUNDSUPPRESSORMODELSFN-57™ (5.7mm) P. 6
45mmNATO ammunition, will result in damagetothesuppressorandprob-
able injury to the shooter.
ÕÕÕÕÕDANGER ÕÕÕÕÕ
"Before performing any installation or maintenance operation, al-
ways remove the magazine from the firearm, open the action, and
visuallyascertainthatthechamberisemptyandtheweaponunloaded.
Failure to do so can result in potential for serious injury to the user
and others in the vicinity.
SUPPRESSOR INSTALLATION/REMOVAL
1. Remove the magazine, open the action, and visually ascertain that the
weapon is unloaded and the chamber empty. Lock the slide in the open
position.
2.If present, remove the thread protector and thread thesuppressor on the
extended,threaded barrel in the Five-Sevenpistolhandtight only.Exces-
siveforceis never necessary.Thesuppressorthreads bottom on the face
ofthebarrel.
3. Removal is the reverse of installation. The suppressor may become hot
withusage.Ifthesuppressormustbedismounted when hot, a protective
glove, such as Nomex, must be worn.
ÕÕÕÕÕCAUTION ÕÕÕÕÕ
"Always read the warning label on any cleaner or solvent, and remem-
ber that virtually all solvents are inherently dangerous and potentially toxic.
Always use adequate ventilation and both skin and eye protection when
using organic solvents and avoid open flames.
CLEANING
Asa general rule (andcontrarytopopular opinion), suppressors havea
longerlife isnoattemptis madeatcleaning.There arenoperfectsolvents for
thecarbondepositedontheinternalpartsby the burning of the powder, and
some carbon residues will slightly enhance performance. Field experience
hasshown that thesuppressorwill outlast anumberofbarrels. Thedesignof
the SFN-57 suppressor is such that any liquid introduced in a cleaning pro-
cess may not drain completely, and its presence will generate more sludge
andresiduewithinthe suppressor than not cleaning.
Regardless, water or water-based solvents must never be used
What does have merit is to occasionally blow out the suppressor with

SOUNDSUPPRESSORMODELSFN-57™ (5.7mm) P. 7
dry compressed air to blow out loose powder granules. Blowing should be
donefirstfromthe rear and second from the front.
Any other attempt at cleaning may well shorten the life of the suppres-
sor. If it becomes necessary, the suppressor can be rebuilt to factory new
condition at a reasonable cost.
WARRANTY STATEMENT
Our "warranty" has been practiced since our personnel started in the
suppressor business in 1976, in a time before legalese and when a hand-
shakeandthissimplestatementsufficed: "If a Gemtech product breaks and
it'syourfault,we'llfixit for a fair price in a timely manner. If it's our fault, we'll
fix it quickly at no charge." This policy born of pride in craftsmanship and
honor has served us and our clients well for over two decades and will con-
tinueinGemtech'sfuture.
Thesmallprintfollows:
The Magnuson-Moss Act (Public Law 93-637) does not require any seller or manufacturer
of a consumer product to give a written warranty. It does provide that if a written warranty
is given, it must be designated at “full” or as “limited” and sets minimum standards for a “full”
warranty.
As do most major firearms manufacturers, Gemtech has elected not to provide any
written warranty, either “limited” or “full,” rather than to attempt to comply with the provisions
of the Magnuson-Moss Act and the regulations issued thereunder.
There are certain implied warranties under state law with respect to sales of consumer
goods. As the extent and interpretation of these implied warranties varies from state to
state, you should refer to your state statutes.
Gemtech certifies that all sound suppressors manufactured by them are free of defects
in materials or workmanship, and that they meet manufacturing specifications at the time of
manufacture.
It is our intent that the customer be completely satisfied with the product. Certain Gemtech
products may be classified as ordnance and/or implements of war and are sold by us with
the specific understanding that Gemtech has taken every reasonable precaution in provid-
ing our customers with inherently safe merchandise, and that we assume no liability what-
soever for unsafe handling or operation by the purchaser or his agents. Gemtech assumes
no responsibility whatsoever and we will honor no claims for damages, regardless of
nature, for physical injury or property damage resulting from careless and/or irresponsible
handling, adjustments to equipment, improper operation, neglect, or abuse.
Gemtech reserves the right to make changes at any time and without notice, in prices, to
change specification or design, to add or remove accessory materials, and to add or delete
items without incurring any obligation.
Warranties specifically apply only to defects in materials or workmanship. They do not
cover misuse by the user, damage due to failure to follow instructions in the manual, use of
inappropriate ammunition, or improper mounting.
Use of ammunition that does not meet SAAMI specifications will void all warranties.
REPAIRPOLICY
Gemtech maintains complete repair facilities for all suppressors manufac-
tured by them or their antecedent companies. Return authorization and shipping
instructions must be obtained prior to return. Contact Gemtech for this informa-
tion.

All Gemtech products are
100% manufactured in the
United States of America.
ATF no longer requires transfer on a Form 5 to the manufacturer for repair.
However, they do require a letter accompanying the weapon detailing the
repairs required. We will require also a photocopy of the front of the owner’s
Form 3, 4, or 5.