BLACKHAWK! ADJUSTABLE CARBINE RIFLE BUTTSTOCK User Manual

knoxx™ replacement adjustable
carbine rifle stock

This BLACKHAWK! Stock is a direct replacement for the standard M4 Sliding butt stock. Rifles with fixed stocks will require the
installation of an M4 Carbine Receiver Extension Assembly (Buffer Tube), M4 Carbine Buffer Assembly and M4 Action Spring.
To convert from a fixed stock to an adjustable stock seek the services of a certified gunsmith or armorer.

WARNING: READ THESE INSTRUCTIONS AND OTHER WARNINGS BEFORE ATTEMPTING TO INSTALL THIS
STOCK ON YOUR FIREARM

The maker of BLACKHAWK! Stocks, BLACKHAWK! Products Group, warns all users of this stock to exercise extreme caution in
the handling of any firearm. Because any firearm is potentially dangerous, the user should successfully complete a recognized
firearms safety course before handling or employing one. Furthermore, recognizing that many of these stocks will be used by
hunters in the field, BLACKHAWK! also recommends that those individuals also complete a recognized hunter safety program.

YOU SHOULD NOT USE OR ATTEMPT TO INSTALL THIS STOCK UNTIL YOU HAVE VERIFIED THE
APPLICATION INFORMATION, HAVE READ AND UNDERSTOOD THESE WARNINGS, AND HAVE READ AND
FOLLOWED THE INSTRUCTIONS FOR USE.

Check to ensure that this BLACKHAWK! Stock is correct for your application. BLACKHAWK! Stocks have been developed for
only the particular models listed in the BLACKHAWK! Stock section of the catalog. Fit information can also be found on both this
Stock’s original packaging and on the website: www.blackhawk.com. YOU MUST NOT USE THIS BLACKHAWK! STOCK
WITH A FIREARM THAT HAS NOT BEEN APPROVED. If in doubt, please contact BLACKHAWK! Products Group at
1-800-694-5263 (phone), 888-830-2013 (fax) or [e-mail] (email).

Even if your firearm is listed as one for which this Stock has been designed, DO NOT use this Stock if it does not appear to fit your
firearm properly. Return it to BLACKHAWK! and we will immediately replace it. Please contact BLACKHAWK! Products Group
at 1-800-694-5263 (phone), 888-830-2013 (fax) or [e-mail] (email) to receive a return authorization.

DO NOT modify this Stock in any manner. DO NOT use this Stock with any firearm that has been modified or is malfunctioning.

ALWAYS refer to the gun manufacturer's recommendations and instructions when told to do so within these instructions.

If you have any questions or comments about any of our BLACKHAWK! Stocks or should need a return authorization, please
contact BLACKHAWK! Products Group at 1-800-694-5263 (phone), 888-830-2013 (fax) or [e-mail] (email).
Additional copies of these instructions can also be obtained by contacting BLACKHAWK! Products Group at those numbers

WARNING: UNLOAD THE FIREARM AND OPEN THE ACTION BEFORE ATTEMPTING THE INSTALLATION OF
THIS STOCK. FAILURE TO DO SO WILL RESULT IN AN UNSAFE FIREARM CONDITION THAT MAY CAUSE
PROPERTY DAMAGE, PERSONAL INJURY OR DEATH TO YOURSELF OR OTHERS.

WARNING: ALWAYS WEAR EYE PROTECTION WHEN PERFORMING ANY OF THE INSTALLATION
OPERATIONS DESCRIBED.

INSTALLATION INSTRUCTIONS:

1. With the rifle pointing in a safe direction and your fingers outside the trigger guard, remove the magazine, open the bolt and both

visually and by touch, make certain there is not a cartridge in the chamber.

. WARNING: Prior to installing stock verify that you have purchased the correct stock to fit your receiver extension tube. Confirm that

2

you have either a “Commercial” receiver extension (Fig A.) or a “Mil-Spec” receiver extension (Fig B.). To determine your receiver

extension tube size simply measure the diameter of the tube. It is crucial that you have purchased the correct size stock. If you have

purchased the correct size tube it should slide fairly easily over the tube and not fit too tight or not have too much wobble. If the stock is

extremely tight DO NOT force the stock onto the tube. DO NOT FORCE a Mil-Spec stock onto a Commercial sized rear extension.

Forcing the stock onto the tube may damage the extension tube or the stock. If you have purchased the incorrect stock, contact

BLACKHAWK! Customer Service for an exchange.

1.170”

1.146”

Figure A (Commercial Tube Cross Section)

3. Slide existing adjustable stock to the rear most position. Pull downward on stock Release Lever and slide stock off back end of receiver

extension. (Figure C)

4. Install BLACKHAWK! Adjustable Rifle Stock by pulling downward on Release Lever and sliding onto back end of receiver extension.

(Figure D)

5. To adjust stock length, grasp and squeeze rear adjustment lever. While squeezing adjustment lever, slide rear portion of stock to desired

length and release lever. Locking pin will automatically engage or “click” into nearest corresponding locking hole. To ensure engagement

of locking pin, push or pull on rear portion of stock. NOTE: At the shortest length setting, some different Commercial sized rear extension

tubes will protrude slightly out rear of stock. To avoid simply adjust the stock to next longest setting.

6. This stock includes a 1” Quick-Detach removable sling swivel preinstalled for a right hand user. To reposition the sling swivel for a left

hand user push the quick detach button located on the top of the swivel and remove the swivel assembly. Remove the preinstalled swivel

base by unscrewing the Phillips Bolt and washer. Reinstall the hardware on the reverse side of the stock and re-engage the Quick-Detach

sling swivel.

7. Prior to using your firearm in an operational environment test all the functions and operations of the firearm to verify correct installation

of the stock.

Figure B (Mil-Spec Tube Cross Section)

fig. C

www.BLACKHAWK.com

BLACKHAWK!®NORFOLK, VA U.S.A. 1.800.694.5263

PGIG001KX

fig. D