Gemtech MK-9K Operation And Maintenance

TM-MK-9K

OPERATION AND MAINTENANCE

OF SOUND SUPPRESSOR

MODEL MK-9K

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: March 2015

     WARNING     

 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 remember that a sound suppressed firearm is just
as dangerous as a non-suppressed one, and the same

safe handling requirements apply.

TM-MK-9K
FIRST EDITION August 1992

SECOND EDITION August 1993
THIRD EDITION November 1994
FOURTH EDITION July 1995
FIFTH EDITION July 1996
SIXTH EDITION April 2005
SEVENTH EDITION March 2015

Published by:

A TI St ar Press

Antares Technologies, Inc.

P.O. Box 140618
Boise, Idaho 83714

Phone: [phone]

COPYRIGHT NOTICE:

©2015 Gemini Technologies, 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 permission of the
copyright owner.

TM-MK-9K

OPERA TIONAL MANUAL FOR

SOUND SUPPRESSOR MODEL

MK-9K™ (9mm)

Manufactured by

GEMTECH

Division of Gemini Technologies, Inc.

P.O. Box 140618

Boise, Idaho 83714-0618

Phone: [phone]

FAX: [phone]

GEMTECH PROPRIETA RY

This document contains proprietary information of Gemtech and is sub­mitted to the receiver in confidence. Any reproduction, use and/or dis­closure of this and/or any portion thereof is expressly prohibited with­out the express written permission of Gemtech

CONTENTS:

Important Warning...........................................................................P. 4

General Description ........................................................................ P. 4

Mounting on Weapons .................................................................... P. 5

Basic Principles .............................................................................. P. 6

Construction....................................................................................P. 6

Ammunition Notes .......................................................................... P. 7

Routine Cleaning............................................................................. P. 8

Field Stripping ................................................................................. P. 8

Reassembly .................................................................................... P. 8

Servicing the Tri-Lock mount........................................................... P. 9

Reassembly .................................................................................. P. 10

Use & Limitations ......................................................................... P. 10

Physical Specifications................................................................. P. 10

Repair Process instructions .......................................................... P. 10

Warranty Statement ...................................................................... P. 10

Assembly Sketch ......................................................................... P. 11

SOUND SUPPRESSOR MODEL MK-9K P. 4



WARNING



 Failure to follow installation and maintenance instructions
detailed in this manual can result in potential for serious
injury to the user and damage to the weapon. Firearm sound

suppressors are user attached firearm muzzle devices, and as
such are subject to improper attachment unless the proper proce­dures outlined in this manual are followed.

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 responsibility to understand and implement its proper use. If
you do not understand the instructions in this manual, please con­tact the manufacturer for further clarification.

Congratulations! Y ou have just obtained the originl, classic 9mm muzzle
suppressor designed for the Heckler & Koch MP5 submachine gun. While
an older design, the MK-9K remains one of the most efficient 9mm subma­chine gun suppressors available anywhere. Before use, please take a few
moments to read this instruction manual. It is not designed for and should

never be used on a center fire rifle.

GENERAL DESCRIPTION

The MK-9K suppressor is a coaxial design exhibiting increased effi­ciency as compared to other suppressors of similar external size and ap­pearance. It is designed to mount on the H&K MP5 submachine gun utilizing
the HK 3-lug barrel. On special order it can be provided to mount on a 1/2x28
threaded barrel. Suppression efficiency is gained through proper design of
the suppressor rather than by using “wipes” or other obstacles touching the
bullet in free flight. For this reason, weapon accuracy is not impaired, and
accuracy may be actually slightly enhanced by tightening of the group size.

 WARNING 

 Failure to follow mounting instructions detailed in this manual

can result in potential for serious injury to the user and damage
to the weapon.

SOUND SUPPRESSOR MODEL MK-9K P. 5

MOUNTING ON WEAPONS

Although some versions of the HK MP5 submachine gun have muzzle
threads, we suggest utilizing the 3-lug mount whenever possible, as it is a
superior and more stable mount. For mounting on other weapons, the sup­pressor can be special ordered to mount on a 1/2-28 threaded barrel.

The MK-9K using the Tri-Lock 3-lug coupler must never be mounted on
a 3-lug threaded barrel without a thread protector in place. Failure to observe
this caution may result in misalignment. If there is any question, we can
provide a suitable thread protector.

When mounting on a threaded barrel, the suppressor should be screwed
on hand tight only . It is import ant to periodically ascertain that the suppres­sor has not unscrewed, which can cause misalignment.

We guarantee alignment of the MK-9K suppressor only on original Ger­man 3-lug H&K MP5 barrels, those converted by S&H Arms Co., or on non­3-lug barrels converted by us. Damage caused by misalignment is not cov­ered under the warranty .

 DANGER 





 Before performing any installation or maintenance operation,



always remove the magazine from the firearm, open the action, and
visually ascertain that the chamber is empty and the weapon unloaded.
Failure to do so can result in potential for serious injury to the user and
others in the vicinity.

GEMTECH TRI-LOCK MOUNTING INSTRUCTIONS

1. Be certain the weapon is unloaded, the magazine removed, the safety on,

and the bolt locked in the open position.

2. Align the grooves in the silencer mount with the lugs on the barrel.

3. Pull the silencer onto the barrel against spring tension until the silencer

can be rotated counter clockwise while holding the weapon in the firing
position.

4. Rotate the silencer 60° until it stops and release pressure on the silencer .

Rock the silencer to be certain that the lugs have engaged the pocket
recesses in the mount.

5. Removal is the reverse of installation. It will be necessary to pull the si-

lencer rearward in order to rotate it 60° clockwise.

SOUND SUPPRESSOR MODEL MK-9K P. 6

SINGLE POINT (THREAD) MOUNTING INSTRUCTIONS

1. Be certain that the weapon is unloaded, the magazine removed, the safety

on, and the bolt locked in the open position.

2. Screw the suppressor onto the barrel threads, being careful to not cross-

thread the suppressor.

3. Tighten firmly hand tight. We advocate the use of Blue Loctite to inhibit

unscrewing during firing.

4. Because silencers using single point thread mounting will unscrew during

use, it is the shooter’s responsibility to frequently check to be cer-

tain that the suppressor remains tightly screwed on the barrel at
intervals not to exceed 1 magazine.

5. We cannot guarantee alignment on barrels not threaded or gauged by us.

We deny liability for injury or damage caused by misalignment or un­screwing of the suppressor.

BASIC SUPPRESSION PRINCIPLES

The sound of a firearm discharging is due to the sudden release of high
pressure propelling gases. The purpose of a suppressor is to reduce the gas
pressure by a combination of increasing the volume for gas expansion, de­creasing gas temperatures, and delaying gas exit from the suppressor.

The MK-9K suppressor is a coaxial design unit, consisting of three
suppression chambers: the inner rear entrance chamber, the inner front cham­ber, and the outer coaxial chamber . The inner rear chamber diverts pressure
into the outer chamber, offering an exceptionally large volume for initial gas
pressure reduction, trapping, cooling, and exit delay . The baf fle stack (cen­tral core) consists of a steep cone (with a notch in the apex) and a series of
precision formed stainless steel baffles. S tainless steel was used for durabil­ity and resistance to gas erosion and corrosion. The baffles are optimally
spaced for maximum gas trapping, cooling and delayed gas release into the
atmosphere.

CONSTRUCTION

The entire suppressor is constructed from hard anodized aircraft grade
aluminum alloys with the exception of the baffles in the central core, which
are precision formed from type 18-8 stainless steel for wear resistance and
durability . No packing materials or consumable part s are utilized.

The suppressor can be partially disassembled for cleaning and routine
maintenance. No tools are necessary for this procedure.

SOUND SUPPRESSOR MODEL MK-9K P. 7

AMMUNITION NOTES

    WARNING    

Never use ammunition that does not meet SAAMI specifications.

All commercial American made SAAMI specification ammunition is safe,
but the origins, storage history, and reason for being surplussed of foreign
made ammunition is not available for evaluation. Although foreign made am­munition is usually safe, this is not always the case. Damage from non­American ammunition cannot be covered under warranty .

The majority of 9mm ammunition is supersonic, and the projectile trav­eling at velocities above 1,100 fps will produce a ballistic “crack” or “sonic
boom”. There are several commercial sources of specially loaded subsonic
9mm ammunition, and for maximum effectiveness, we suggest the use of
this type ammunition. Although special 9mm subsonic ammunition has a
bullet muzzle velocity below 1,100 fps, the higher bullet weight results in a
significantly higher bullet kinetic energy .

The majority of subsonic 9mm ammunition is loaded utilizing bullet
weights of 147 grain or heavier. Subsonic ammunition utilizing bullet weight s
of 155 grain or more is apt to be significantly overpressured in some weap­ons, especially the HK MP5. 147 grain FMJ and JHP bullets for 9mm reload­ing are available from a variety of suppliers, including Hornady and Speer . Do
not use cast lead bullets. Loading data for 9mm subsonic ammunition is
available from a number of sources, including the Speer Supplement (avail­able from Speer for their 147 grain TMC bullet s), and from Accurate Arms for
use with their powders. However, we caution against any attempt to hand

load beyond recommended SAAMI specifications.

Commercial subsonic ammunition is available in 158 grain FMJ from
Israeli Military Industries and in 147 grain bullet weight from Winchester,
Remington, Federal, CCI, and others in both full metal jacket and hollow
point styles. We have found that although this ammunition remains subsonic
in pistols, it may not remain subsonic in the longer barrel of the Heckler &
Koch MP5 submachine gun. The user will need to experiment with different
brands. Ammunition with bullet weights over 154 grains is discouraged by
H&K. Although some have suggested that the 9mm subsonic cartridge is
“downloaded,” we believe users should be aware that this ammunition is
anything but an anemic load with kinetic energies and pressures signifi­cantly greater than standard 9mm ball ammunition.

Use of corrosive ammunition, and evidence of its use, will void the war­ranty .

SOUND SUPPRESSOR MODEL MK-9K P. 8

ROUTINE CLEANING

Our experience suggests that total disassembly for cleaning is not nec­essary, and for this reason the inner core is sealed to maintain optimum
positioning of the parts. Field stripping and cleaning should be performed
every 2,000 rounds. Because of molten lead splattering from the heat gener­ated by friction with cast bullets and bullet lubricants, ammunition loaded
with cast lead bullets should never be used.

After field stripping, some cleaning can be performed by immersing the
central core of the suppressor in a suitable solvent.

Cleaning of the central core is optional and consists primarily of flushing
out unburned or partially burned powder residues. There are no perfect sol­vents for the carbon deposited on the internal parts by the burning of the
powder. We have found, however , that Varsol automotive parts cleaner or a
mixture of 3 parts mineral spirits and 1 part T ype A Automatic T ransmission
Fluid are among the better solvents for suppressor cleaning. We suggest
against the use of water-based solvents. Never use solvents containing
ammonia, which can damage aluminum parts. This includes Hoppe’s, Sweets,
and “GI” bore cleaner. Never use water or water-based solvent s, which
can damage aluminum. Ultrasonic cleaners have limited value, because
they require water-based solvents.

 CAUTION 

 Always read the warning label on any cleaner or solvent, and

remember that virtually all solvents are inherently dangerous and po­tentially toxic. Always use adequate ventilation and both skin and eye
protection when using organic solvents.

FIELD STRIPPING (Partial Disassembly)

Unscrew the front end cap, which is threaded into the central core of the
suppressor. This will release the outer tube, which is held in compression by
the front end cap and rear mount. A small neoprene “O” ring in a groove in the
rear mount provides a gas seal. Remove the outer tube.

Unscrew the rear mount from the central core. Do not attempt to disas­semble the central core. At this point the suppressor can be cleaned by
immersion.

Although complete disassembly of the central core is theoretically pos­sible, we feel that so doing is not necessary and is without merit.

We recommend against the use of any water based solvent or cleaning
materials.

SOUND SUPPRESSOR MODEL MK-9K P. 9

SERVICING THE 3-LUG MOUNT

The Raptor™ 3-lug mount can be easily disassembled for servicing.

1. Unscrew the knurled cap from the body.

2. Remove the spring-loaded piston from the mount body. Remove the spring.
Service consists of:

1. Replace the O-rings if necessary. The O-ring in the body can be removed
with a dental pick. O-rings are Viton (neoprene must not be used).

2. Thoroughly clean the spring-loaded piston inside and out. Made of stain­less steel, it can be cleaned with red Scotchbrite or fine steel wool moist­ened with WD-40.

3. Coat the outside of the piston with grease as well as the inside of the
knurled cap. Lightly coat the inside of the mount body . Suitable greases
include marine bearing grease, available at stores that sell boat trailers.

4. Insert the spring in the mount body followed by the piston (small end first).
Replace the cap and screw hand tight. Do not use thread adhesives.

It is not unusual for a small amount of grease to be forced through the
small vent hole in the knurled cap. This hole is to prevent pressurization of
the mount.

SOUND SUPPRESSOR MODEL MK-9K P. 10

REASSEMBLY

Reassembly is the reverse of disassembly. When reassembling the
suppressor, we suggest use of a thread lubricant and anti-seize compound,
such as a T eflon compound or one of the many quality commercial anti-seize
materials.

The holes in the wall of central core are in the rear section. After coating
the threads with anti-sieze compound, screw the rear mount hand tight into
the rear of the central core.

Be certain that the Viton “O” ring in the rear mount is intact, and replace
if worn or broken. Replacements are available at most well stocked hardware
stores or stores selling hydraulic tools and are 1-3/4" x 1/16".

Coat the inside of the end of the outer tube with either a lithium based
grease or Vaseline in order to facilitate disassembly and reduce binding of
the “O” ring. Replace the outer tube and screw in the front end cap to secure
all parts in place. This completes the reassembly.

NOTES ON USE

Use of this suppressor on a centerfire rifle will exceed the design pa­rameters, leading to structural failure of the suppressor and possible injury to
the user.

Because of the design of this suppressor, heating of the outer tube
during fully automatic fire is minimized. If firing the weapon causes the outer
tube to heat to the point of being too hot to touch, then the suppressor should
be allowed to cool until it can be handled without discomfort before resuming
fire. Because of this indication of overheating, we suggest against the use of
a protective Nomex cover.

PHYSICAL SPECIFICATIONS

Caliber 9mm Parabellum (only)

Length 7.5 inch (191 mm)

Diameter 2 inch (51 mm)

Weight 20 ounce (570 gm)

LIMITED WARRANTY STATEMENT

Gemini Technologies, Inc., dba Gemtech, warrants to the initial retail
purchaser that Gemtech products will be free of defects in workmanship or
material and that the product meets manufacturing specifications at the
time of manufacture. This warranty is limited to the repair or replacement of
the product. This express limited warranty is exclusive and no other express
or implied warranty is otherwise provided.

GEMTECH MAKES NO WARRANTY OF MERCHANT ABILITY OR
FITNESS FOR P ARTICULAR PURPOSE.

Product technical specifications and/or designs may be changed
without notice. This warranty does not cover negligence, misuse, careless
or improper handling and/or operation, abuse, unauthorized adjustments or

SOUND SUPPRESSOR MODEL MK-9K P. 11

modifications, improper mounting/installation, ordinary wear and tear, the
failure to follow manufacturer instructions and/or the use of inappropriate or
defective ammunition.

Gemtech shall have no liability for incidental or consequential
damages and under no circumstances will Gemtech be liable for
personal injury, property damage or economic loss.

This warranty and disclaimer is subject to all applicable laws some of
which may limit these terms.

WARRANTY REPAIRS: Return of a Damaged Suppressor

If a suppressor is damaged due to a manufacturing defect once it has been
fired, it may be returned to Gemtech for repair or replacement. Determination to
repair or replace is made solely at our discretion and only after we have had the
opportunity to examine and determine that the cause of the damage is due to a
manufacturing defect. It is the responsibility of the customer to cover shipping
costs and insurance to return the suppressor to Gemtech for inspection or repair.
Gemtech will pay any reasonable shipping and insurance costs to return the unit
to you.

To assure proper legal procedures for any repair returns, fill out and provide a
copy of the General Service Form with any packages sent to us. (Visit gem­tech.com, navigate to
the fillable General Service Form.pdf or call 208.939.7222)

BATFE no longer requires transfer on a Form 5 to the manufacturer for repair.
BATFE does require a letter accompanying the suppressor detailing the repairs
or modifications required (satisfied by a completely filled out General Service
Form). BATFE also requires proof of ownership satisfied by a photocopy of the
front of the owner’s Form 3, 4, or 5.

NOTE: BATFE prohibits transferring the serial number to a new outer tube in
the case of damage to the tube. Tube damage rendering the suppressor unsafe
will require a new suppressor.

Customer Support/Return and Repair Policies to download

All Gemtech products are
100% manufactured in the
United States of America.