Carbine and Rifle Modstock
|Congratulations on your purchase of the VLTOR Modular Firearm Buttstock,
(a.k.a. Modstock). We hope you will appreciate the quality of the
construction and the versatility the Modstock offers. Please read
this Installation and Operation Manual thoroughly before handling
the Modstock and/or the contents of the box.
Before attempting installation, please read the warnings and notes first.
WARNING: The Installation of the any Vltor
Modstock System should be preformed by a qualified gunsmith or qualified
United States military small arms technician.
LEGAL NOTE: The Vltor Modstock system for
AR type rifles can be used on some post-ban (1994 Crime Bill) configured
firearms. The only Modstock system allowed on a post-ban (1994 Crime
Bill) rifle is the Rifle Modstock and only when mounted to a Rifle
Receiver Extension (Colt part# SP61574). The use of a Collapsible
Stock Receiver Extension on a post-ban (1994 Crime Bill) rifle is
strictly prohibited by federal law (Section 922 of title 18, United
States Code). Vltor Weapons System recommends the installer and/or
the firearm's owner to check with local, state and federal law before
attempting installation/possession of any product manufactured or
sold by Vltor Weapon Systems . Vltor Weapon Systems is not responsible
for the installation of, use of the Modstock system, or any other
related Vltor Weapon Systems product.
A note to qualified installers:
Refer to the current United States Military Technical Manuals or Colt
factory technical manuals for proper tool needs and technical data,
such as, torque specifications. All parts installed during the conversion,
including Vltor Modstock components, should be new and certified by
Colt and/or the United States Military.
Important Note: The Vltor Modstock System will fit only Colt/military dimensioned,
collapsible stock receiver extensions. Other makers' collapsible stock
receiver extensions will fit improperly and should be considered unsafe
to use. These inferior receiver extensions are not recommended for
use with the Modstock system under any circumstances.
AR Rifle Series
Removal of existing buttstock / installation
of Modstock for rifle:
Located at the rear upper portion of the butt plate is a slotted screw.
With the screw completely removed slide the complete stock assembly
off the receiver extension.
Install the rifle Modstock over the receiver extension, making sure
the Modstock's forward indexing pin aligns to the indexing hole, located
on the back of the rifle's receiver located just below the receiver
extension mounting point.
For "A1" length (ARM-1 series) Modstocks:
With the A1 length Modstock installed, insert the Modstock
Cap, (supplied with the Modstock kit).
Next, with the Butt Cap in place, install the new A1 length Butt Cap
Screw (supplied with Modstock kit, known as Colt part #SP62601). Thread
and torque screw to proper specification as required in the United
States military or Colt factory technical manual.
For "A2" length (ARM-2 series) Modstocks:
With the A2 length Modstock installed, insert the buttstock spacer
(found only on A2 versions of the AR rifle series, Colt part #SP64578),
followed by the installation of the Modstock
(supplied with the Modstock kit). With the cap in place install a
new Butt Cap Screw (found only on A2 versions of the AR rifle
series, Colt part #SP64577). Thread and torque screw to proper
specification as required in the United States military or Colt
factory technical manual. (The Buttstock Spacer, Colt part #SP64578
or the Butt Cap Screw, Colt part #SP64577 are not supplied with the ARM-2 Modstock
AR Collapsible Stock Carbine Series
Removal of existing collapsible buttstock
/ installation of collapsible Modstock:
To remove the existing collapsible buttstock, two steps need to be
taken simultaneously. Step 1: retract/disengage the lever lock pin.
Step 2: slide the stock to the rear of the receiver extension until
the stock assembly separates from the receiver extension. To install
the new collapsible Modstock assembly, reverse the removal process.
Installation of the Rifle Modstock to the collapsible buttstock
(Before proceeding, refer to Legal Note/Disclaimer at the
beginning of the manual.)To remove the existing collapsible stock,
refer to the pervious paragraph. Next, install the Rifle Modstock
onto and over the collapsible receiver extension. As mentioned before,
the AR Modstock will only fit Colt/military dimensioned receiver extensions.
The Colt receiver extension (Colt part #SP64072) is available through
Colt and/or through a Colt Authorized parts distributor.
When mounting the Rifle Modstock to the collapsible stock receiver
extension, two different lengths or positions can be achieved. The
first position is the
position known as "position A". The second position of the stock
is an extended length of 0.800 of an inch longer then position A.
position is "position B". The Rifle Modstock features two
Lock-Pin access ports. Each port allows the stock to be placed
in either Position A or B. To lock the Modstock into position A, place
the Manual Lock-Pin access port under the receiver extension mating
slot. The slots are located beneath and within the collapsible stock
receiver extension. The access port for position A is located along
the mounting beam near the center of the stock. This port must be
indexed to the furthest most stock placement slot of the collapsible
stock receiver extension. To achieve position B, the forward access
port (found next to the forward sling mounting hole, must be aligned
with the closest indexing slot near the firearm's receiver of the
collapsible stock receiver extension. This slot would normally be
used when the collapsible stock is in the "standard/collapsed" position.
To lock the stock into either position the Manual Lock-Pin must be
installed. The Manual Lock-Pin is equipped with every rifle Modstock
kit. The Manual Lock-Pin assembly consists of a steel indexing pin
and a pivoting composite material latch. To lock the Modstock into
position A, install the Manual Lock-Pin into the position A access
port, inserting the pin into the receiver extension's slot. With the
pin installed, begin to rotate the Manual Lock-Pin, Locking Latch
until it contacts the ramping surface (the bridge of material long
the mounting beam). Next, by applying pressure to the Locking Latch,
the latch will ramp-up and rotate to a complete locking position,
simultaneously forcing the Manual Lock-Pin upward in the receiver
extension slot. To unlock and remove the Manual Lock-Pin, reverse
the installation process.
Installation of Cheek Weld Adapter or Modstock Accessory Compartment:
The installation of the Cheek Weld Adapter and Accessory Compartment
are similar. Both items feature locking fingers on the upper portion
and mounting flange at the base. Future Modstock accessories may differ
in ways of mounting. To install, first plan placement for the chosen
accessory, then insert the locking fingers into the square mating
holes along Modstock's body. Next, pivot the accessory downward, until
the accessory's mounting flange contacts squarely against the surface
of the stock. Immediately before the two surfaces contact, the parts
will first "snap" together, aiding in it's locked position.
Next, to better secure mounting of accessories, the use of
Hardware should be used. All Modstock kits come equipped with
two Accessory Nuts and two Accessory Mounting Screws. To install,
index and insert the Accessory Nut into the accessory and through
the Modstock mounting beam. After insertion of the Accessory Nuts
install the Accessory Mounting Screw on the opposite side of the Accessory
Thread the Accessory Mounting Screw(s) to a snug fit with the aid
of a 3/32 hex wrench (which is provided with the Modstock kit). The
combination of the Accessory Mounting Screw and Nut will sandwich
the accessories and the Modstock together.
Installation of Accessory Compartment Cap:
Every Modstock kit is equipped with two Accessory Compartments (long
compartments for the rifle Modstock and short compartments for the
collapsible Modstock). Each Accessory Compartment is equipped with
two Accessory Compartment Caps. The caps are easy to operate and feature
a rotary-lock function. Before cap installation, first make sure the
Accessory Compartment is ideally placed on the Modstock, allowing
access to either end of the Accessory Compartment. Some users may
prefer to block one end of the Accessory Compartment, by mounting
close to the backside of the butt plate or near other accessories.
If so, first install the cap before mounting the Accessory Compartment.To
install a Compartment Cap, place the cap in hand, locate and place
the lever downward. At 180-degrees away from the lever there is the
access notch (top). Before installation, the notch must index with
the locking tooth, found at the 12 O-clock position of the Accessory
Compartment. After properly indexing both parts insert the cap. With
the cap fully inserted the next step is to
the cap into the locked position. There is only one way to rotate
the cap to the locked position. To lock, rotate the Compartment Cap
lever towards the Modstock's mounting surface. When the cap rotates
two functions occur; first, the cap lever detents over the Accessory
Compartment support arm, and second, the cap is forced into the compartment
bore by means of a camming action. The camming action occurs when
the Compartment Cap is forced into the Accessory Compartment with
aid from the locking tooth.
Installation tip: Some may find the installation and removal
of the caps to be difficult. To aid in the process, apply a dab of
petroleum gel or silicon grease to the rubberized material, which
seals to the inside of the compartment. The lubricant will also aid
in a better seal between cap and compartment.
The operation of the Uncle Mike's Quick Detachable Sling Swivel:
The Vltor Modstock system has the ability to mount a sling, both conventionally
and by quick detachable means. To allow the sling to be quick detachable,
Vltor has equipped every Modstock kit with one Uncle Mike's Quick
This sling swivel is retained within the stock by means of
retractable locking ball bearings. To install the QD sling swivel
into the Modstock, first, insert the body of the sling swivel into
the Sling Swivel Locking Sleeve located within the Modstock. With
the Sling Swivel partial installed complete the insertion by applying
pressure to the button. The button is located on the exposed portion
of the sling swivel's body. By pressing the button, the locking ball
bearings will retract, allowing the total insertion of the sling swivel
into the Sling Swivel Locking Sleeve. To remove the QD sling swivel
simply reverse the installation process.
The Modstock has multiple mounting points for the Uncle Mikes QD Sling
Swivel. For every one Sling Swivel Locking Sleeve molded in a Modstock
the Uncle Mike's QD Sling Swivel can mount ambidextrously to either
side. For example, the rifle Modstock has two Sling Swivel Locking
Sleeves giving the operator the choice of four mounting possibilities.
The collapsible Modstock only features one Sling Swivel Locking Sleeve
which gives the operator a two sling mounting choices.
If you encounter any difficulties operating
the Modstock system, or if your qualified gunsmith/technician has
questions regarding installation of the Modstock system, feel free
to contact Vltor Service Department, either by telephone: (520) 408-1944
or by email:
Colt is a registered trademark of Colt's Manufacturing Company, Inc.
Uncle Mike's is a registered trademark of Michaels of Oregon Co.
Modular Firearm Buttstock
is Patent Pending.
Modular Firearm Buttstock - Patent 6925744.
Other Vltor patents are
Copyright 2002 - 2008 VLTOR Weapon Systems
All Vltor logos are registered Trademarks.