UTG AR-15 A2 Fixed Buttstock
Complete Assembly
UTG AR-15 A2 Fixed Buttstock
Complete Assembly UTG Black
Storage Compartment
Note:
All component terms used in this write-up are terms used in
the Disassembly Views of Bushmaster XM15 E2S Rifle, which I
have included at the end of the article. Since I could not
find an IPB (Illustrated Parts Breakdown) specific to the
“SRC”, this one will suffice for general component
identification.
For the most part (and there may be exceptions), the
collapsible stocks that are usually mounted on new AR15 MSRs
are made for the masses and different size operators. I prefer
a solid stock, full or carbine length. Thus, when the
opportunity presented itself to personalize my Windham
Weaponry “SRC”, the stock was the first to go. Well, the third
to go after installing a good optic and a good set of Magpul
steel flip sights.
The UTG A2 fixed stock is a rifle-length fixed stock that is
slightly shorter than the collapsible stock (that came with
the WW “SRC”) when fully extended, but slightly longer than
the A1 stock that is more in proportion to carbine-length
MSRs.
The UTG A2 fixed stock is molded from an advanced impact
resistant polymer and includes a storage compartment so that
you can conveniently store your cleaning kit or replacement
parts, a 4.8 ounce Buffer Assembly, Action Spring (a.k.a.,
buffer spring), Receiver Extension, Buttcap Spacer and
Buttplate Screw. My particular stock is black but other colors
are available.
The Product Box
The Product Bag
The Product – Everything
Necessary For Installation
The UTG A2 fixed stock is shipped within plastic and within a
cardboard box.
All the inner parts are installed in the stock and held in
place by an end cap that includes a cautionary label; “Spring
and Buffer are compressed inside. Please point the cap
downward and open with great caution to avoid any sudden
spring release.” Believe me that they mean it.
Now, to be clear, this was not my first rodeo with the UTG A2
stock and the Windham Weaponry “SRC” has a similar stock had
been mounted on a previous occasion. Much to my chagrin, the
earlier stock was a dark grey that I did not think fit in with
the looks of the firearm after it was mounted. I made a
decision was made to change out the stock with a black one and
use the innards that came with the new stock for a Magpul
AR-15 MOE Rifle Stock Polymer Black MAG404-BLK that is going
to be mounted on the Ruger AR 556.
Textured
Enough
Buttplate WithS t o r a g e
Storage Access Q u i t e A
for
Few
Slim-Jim
Snacks
and
Other
Essentials
The UTG A2 fixed stock is nicely textured and also
incorporates the “trap-door” storage area as does all UTG A2
stocks. The butt pad is nicely fitted to the stock and
incorporates diamond checkering for a firm hold when pressed
against the shoulder. The trap door and latch feels sold are
also made of polymer material. The buttstock also incorporates
a sling mount that is held into place by the Rear Swivel
Screw.
While no showpiece, this A2 stock assembly augments the looks
of the Windham Weaponry “SRC” and is highly functional for me.
Total unit weight is 25 ounces.
The stock is manufactured in Taiwan and should feel right at
home when Wolf Gold .223, 55-grain, FMJ ammunition (also made
in Taiwan) is being thrust out of the muzzle.
This would normally end the review for me, but I wanted to
share information about replacing your collapsible stock with
this one, some ways to make it better, and a few areas that
you need to be concerned with during the swap-out from one
stock to another. If this interest you, please read further.
REMOVAL AND REPLACEMENT:
If you are not confident in replacing the collapsible stock
with the A2 stock, seek out a certified gunsmith to perform
the work for you. However, if you are confident that you can
replace the collapsible stock with the A2 stock, continue
reading for directions to do so.
Tools:
The tools that you will need to remove the collapsible stock
and install the A2 stock follow:
An AR wrench (to remove the Receiver Extension Locking
Nut, to remove the existing stock, and install the
“rifle” length tube needed for the A2 stock) or have a
friend that has one and is willing to help you (as I
did).
If you do not have an AR tool, an adjustable wrench or a
5/8-inch open end wrench.
A quality, hollow-ground flat-tip screwdriver to fit the
Buttplate Screw. Note: I highly recommend the Weaver
Multi-Bit Tool Kit. If you have this kit, the Leupold
Hex Bit (#203) is a perfect fit for the Buttplate Screw.
Patience
#AllSpringsMatter
#AllSpringsMatter is the hashtag for the day when attempting
to replace your existing stock with this one. Two springs are
particularly susceptible to flying to locations unknown by
modern man; the Takedown Pin Spring and the Buffer Retainer
Spring. The latter can be found rocketing skyward (along with
the Buffer Retainer) if not restrained and the former can be
easily damaged (as I found out with the first outing with this
stock). Wear eye protection!
NOTE TO READER:
Since including images really messes up instructional steps, I
have included reference images at the end of the article.
Removing the Collapsible Stock:
Safety First – Always! To begin the swap out, the firearm
needs to be safety checked for existing installed ammunition.
In other words, unload and safe the weapon.
1. Separate the upper from the lower and set the upper
aside; you will not need it for the remainder of this
disassembly.
2. Re-orient the lower as needed to access the Buffer
Assembly. Caution! The Buffer Assembly is under spring
tension. Press down on the Buffer Retainer while holding
the Buffer Assembly in place.
3. Slowly slide the Buffer Assembly out from the Receiver
Extension.
4. Slightly loosen the Receiver Extension Castle Nut with
the AR Wrench.
5. Hold the lower upright (butt in the air). Place a finger
across the End Plate. This plate holds in the Takedown
Pin Spring and Takedown Pin Detent in place. We want the
End Plate to remain holding the Takedown Pin Spring
while unscrewing the Receiver Extension Castle Nut. The
End Plate must be removed straight back to the rear lest
you bend this spring.
6. While holding the End Plate in place, slowly unscrew the
Receiver Extension Castle Nut completely.
7. With the finger holding the End Plate, allow the End
Plate to move rearward. Ensure that you do not allow the
End Plate to twist; this movement could damage the
Takedown Pin Spring.
8. Once the Takedown Pin Spring’s tension has released,
remove the Takedown Pin Spring and set it aside for use
with the A2 stock. (Note: I like using magnetic trays
for holding parts like these; they are available at most
auto parts stores or Harbor Freight.) Note: At this
time, there is no spring tension applied to either the
Rear Takedown Pin or to the Takedown Pin Detent. Care
must be taken to prevent these parts from falling out.
On the other hand, you can remove these parts and set
them aside for use when assembling the new A2 stock.
Note the orientation of these parts upon removal to
ensure that they are properly installed during assembly
of the new stock.
9. CAUTION! The Buffer Retainer is under spring tension.
Press the Buffer Retainer down until it just clears the
Receiver Extension (a.k.a. Buffer Tube). While holding
10.
11.
12.
13.
the Buffer Retainer down, slowly unscrew the buffer tube
just enough to clear the Buffer Retainer.
Slowly release the Buffer Retainer and Buffer Retainer
spring until spring tension is released.
Remove the Buffer Retainer and Buffer Retainer spring.
Set aside for future assembly.
Completely unscrew the Receiver Extension from the lower
(which also includes the collapsible stock).
Optional Step: At this point, I like to apply a thin
coat of Lubriplate 130-A to the Takedown Pin and also to
the Takedown Pin Detent.
This completes the removal of the expandable stock from the
MSR.
Installing the UTG A2 Stock:
Before I get to the instructions for installing the A2 stock,
I would like to interject some information regarding how to
make the A2 stock relatively rattle-free.
One of the many complaints about this stock is that it
rattles. The rattle is primarily caused by excessive play of
the Buttstock Spacer. Another mention is the Action Spring
“sproing”, which is caused by the Action Spring contacting the
side of the Receiver Extension. The Action Spring does sing,
but it sings a welcome tune. Also, the rear compartment latch
is a little noisy, being plastic and not being tight with the
Buttplate. A ½-inch butt pad (like a Limbsaver) takes care of
that and makes up for the LOP lost by converting to the A2
stock. Besides, the latch noise goes away when you shoulder
the firearm.
Let’s look at the rattle caused by the Buttstock Spacer.
The distance from the rear internal detent for the spacer, to
the front of the stock, is approximately 10.25 inches. The
length of the receiver extension, including the buttcap
spacer, is 10 inches. In other words, there is .25 inches of
play between the end of the spacer and the buttplate. This is
the reason that these types of stocks rattle. What is needed
is a spacer(s) that will fill the ¼-inch gap, but allow some
compression so that the stock properly seats against the
lower.
While I can’t guarantee a rattle free stock (I can’t do
anything about the buffer tube and spring, nor for the rear
storage latch), I can guarantee that the rattling will not be
caused by the buttstock spacer. To eliminate any movement from
the stock on the lower, and rattles caused by a loose
buttstock spacer, takes three o-rings commonly found at auto
parts stores, Lowes, or harbor Freight. The o-rings provided
the necessary spacers while providing a soft compression and a
tight stock to lower mating.
In the indent of the lower,
where the stock mates,
insert a 012/P9 o-ring. Note
the hole for the Takedown
Pin Spring
In the indent of the lower, where the stock mates, insert a
012/P9 o-ring. This o-ring prevents movement between the stock
and the lower
At the tightening lug of
the receiver extension,
install a 113/P14 o-ring.
This o-ring provides a spacer.
At the end of the Buttcap
Spacer, install a 115/P18 0ring.
At the end of the Buttcap Spacer, install a 115/P18 0-ring.
This o-ring butts against the Buttstock well where it receives
the Buttstock Spacer.
When the stock is tightened against the lower, the o-rings
provide a cushion to prevent stock movement and quiet an
otherwise loose and noisy Buttstock Spacer.
At this time, you may want to apply a dab of blue threadlocker to the upper buttplate screw. This will help to prevent
the top Buttplate Screw from backing out during recoil, but
allows for easy removal of the screw if necessary.
So, let’s get started with the installation of the UTG AR-15
A2 Fixed Buttstock Complete Assembly.
1. Perform a test fit of the Receiver Extension to the
lower.
2. Install the Buffer Retainer and Buffer Retainer Spring.
3. (R1) Check the clearance of the Receiver Extension and
the Buffer Retainer. The receiver extension should hold
the Buffer Retainer in place and allow up and down
movement. If the Receiver Extension places a bind on the
Buffer Retainer, with the Receiver Extension tightened,
some very minor filing of the Receiver Extension with a
fine round file may be required to achieve the proper
clearance. Use a scribe or marking device to mark the
point where the Receiver Extension meets the Buffer
Retainer. Press the Buffer Retainer down and remove the
Receiver extension. Ensure that the Buffer Retainer does
not fly out of the lower. Perform minor filing and test
fit as explained previously.
4. Once the Receiver Extension to Buffer Retainer is
correct, install the Receiver Extension and tighten it
with the AR wrench, adjustable wrench, or a 5/8-inch
open-end wrench. DO NOT OVERTIGHTEN!
5. Hold the lower with the rear of the lower upward and
install the Takedown Pin (if removed). Note that the
slot in the Takedown Pin faces the rear of the lower.
6. Install the Takedown Pin Detent into the rear of the
receiver. Note that there is no wrong way to install the
Takedown Pin Detent.
7. (R6) Install the Takedown Pin Spring.
8. Install the Buttcap Spacer on to the Receiver Extension.
9. Slide the A2 buttstock over the Receiver Extension.
There is a detent in the lower in which the protrusion
on the front of the buttstock mates. Prior to engaging
the Takedown Pin Spring with the front of the buttstock,
align the buttstock so that protrusion and the detent
match. Slowly push the buttstock straight down,
compressing the takedown pin spring evenly, until the
buttstock is properly seated. Note: If you bend the
takedown pin spring, it must be replaced. I would advise
that you purchase a spring kit for your AR before
attempting to replace the stock, so that a spare
takedown pin spring is available – just in case. Trust
me, I know about these things and about this spring
(mine was damaged the first time around).
10. While keeping constant pressure on the stock against the
lower, install and tighten the top Buttplate Screw.
Note: Use of a hollow-ground flat tip screw driver of
the appropriate bit size will prevent damage to the
screw is highly recommended.
11. Install the Action Spring and Buffer Assembly into the
Receiver Extension.
This completes assembly of the A2 stock to the MSR.
If you opted to install the o-rings, the stock will be as
rattle-free as it can be.
UTG
A2
Stock
Fully
Assembled, Slung, and Ready
To Go
Install the lower to the upper and you should be good to go.
Enjoy your new rifle-length A2 stock.
SUMMARY:
If you prefer fixed stock over collapsible stocks, the AR-15
A2 Fixed Buttstock Complete Assembly UTG Black Storage
Compartment is a good choice. Note that the UTG A2 stock comes
in different lengths: the rifle stock (what this article is
about), a carbine stock (a shorter Receiver Extension, Action
Spring, and Buffer Assembly. The Buttcap Spacer is not
needed), and a compact A2 stock (very short).
The beauty of installing the A2 “rifle-length” stock is that
if you decide to install a Magpul or other that uses the
“rifle-length” Receiver Extension, it is a quick and easy swap
out. I plan on installing a Magpul AR-15 MOE Rifle Stock
Polymer Black MAG404-BLK on the Ruger AR 556, and I can use
the parts contained in this kit for that installation.
PICTORIAL REFERENCES:
Takedown Pin Spring
Takedown Pin Detent
Takedown Pin
Buffer Retainer Spring
Buffer Retainer
Hold the Receiver Extension
End Plate While Unscrewing
the Castle Nut to Prevent
Damage to the Takedown Pin
Spring
Press the Buffer Retainer
Down While Unscrewing the
Receiver
Extension
To
Prevent Loss of the Buffer
Retainer and Buffer Retainer
Spring
(R1) The Buffer Retainer and
Spring is Held Captive by
the Receiver Extension
Use
Caution
when
Assembling the Stock to
the Lower – Do not
Damage the Takedown Pin
Spring!!
ADDITIONAL REFERENCES:
UTG AR-15 A2 Fixed Buttstock Complete Assembly UTG Black
Storage
Compartment:
http://www.cheaperthandirt.com/product/ARR-205?td_source=searc
h
Source for O-rings: Storehouse 397 piece O-ring Assortment,
Harbor Freight
ERGO Grip AR-15 Lower Receiver Spring Replacement Kit 9 Piece
4612:
http://www.cheaperthandirt.com/product/9-105458?td_source=sear
ch