Using a Collapsable Stock (CAR) Stock on an AR-10
 

Overview:

One of the items that I longed for during the ten years of the Clinton Ban on cosmetic features on Semiautomatic weapons was a Collablse Stock version of the SR-25 or AR-10 that would be similar to the Knights SR-25K but I was never willing to spend the money that those limited edition guns were worth for a piece I intended to shoot.

Happy was I the day when Armalite announced that they had developed and started selling a CAR stock assembly for the AR-10 especially when this became available about six months before the death of the crime bill. I ordered one the same day I learned they were available and stuck it away for assembly after the crime bill died and following is a revew that I had posed in several places on the web but I am moving here as on other boards my posts seem to get lost...

Here is a pic of my Baby:

http://quarterbore.com/images/ar-10_picset_05.jpg
[url=http://quarterbore.com/forum/viewtopic.php?t=104}More Photos here!{/url]

--- On to the Review ---

The Stock itself

The Armalite CAR stock for the AR-10 is a ribbed stock that LOOKS very much like the Rock River Arms style stock that we have become accustomed to. The Plastic stock itself looks to be the same external size as my RRA CAR stock that I have to compare it to but it seems to me that the internal hole for the buffer tube seems to be just a little larger but not so much that the parts don't swap (more below). One thing that is for certain is that the Armalite stock is a better mold then the RRA stock I have but I do think they are the same otherwise.

http://www.quarterbore.com/images/car10_b.jpg
Top: RRA 223 CAR Stock Assembly- Bottom Armalite CAR Stock Assembly
NOTE: The springs and buffer is pushed to the rear of the buffer tube!

http://www.quarterbore.com/images/car10_e.jpg
Top: RRA 223 CAR Stock - Bottom Armalite CAR Stock

http://www.quarterbore.com/images/car10_f.jpg
Left: RRA 223 CAR Stock - Right Armalite CAR Stock
Note: The Armalite stock is more robust and the internal hole is if anything LARGER on the Armalite stock! I am looking for my calibers to measure but the RRA buffer has a sloppy fit while the Armailte buffer tube is tight! The Armalite tube barely goes into the RRA CAR stock!

http://www.quarterbore.com/images/car10_g.jpg
Left: RRA 223 CAR Stock - Right Armalite CAR Stock
Note: Same as above... this has to be a strange illusion[%|]... I need to find the calibers...!

The Buffer Tube

The Buffer tube on the RRA CAR stock is THE SAME LENGTH externally and same approximate diameter as the Armalite CAR stock with the Armalite seeming perhaps just a little larger in diameter based on how the tubes fit into the stocks. The new AR-10 CAR stock is about 3/4-inch longer internally however which is a major issue for people planning to use an AR-15 CAR stock on their AR-10.

The threaded area of the Armalite buffer tube is identical to the RRA stock. The only real difference between the buffer tubes is that the holes for the six positions are in different places. The Armalite stock does not collapse as far as the RRA stock but it's open length is the same. The way it looks to me is that the RRA stock will collapse about an additional 0.5-inches or so more then the new CAR stock for the AR-10 which is fine by me.

http://www.quarterbore.com/images/car10_c.jpg
Top: RRA 223 Buffer Tube - Bottom Armalite AR-10 Buffer Tube

The Buffer Spring

When I first got the stock I automatically tried to compare the new AR-10 CAR spring to that of the RRA 223 stock. Following is a photo of these two units:

http://www.quarterbore.com/images/car10_d.jpg
Top: RRA 223 CAR Stock Assembly- Bottom Armalite CAR Stock Assembly

As months went on and the crime bill finally dies I pulled apart my AR-10 and discovered that the better comparison would have been to compare the spring in the new AR-10 CAR stock to the spring in the AR-10 A2 stock. As it turns out, the Buffer Spring in my Armalite AR-10A4 looks to be IDENTICAL to the spring that came with the Armalite CAR stock assembly! [red]Yes[/red], I said they look to be [red]IDENTICAL[/red]! See the pics that follow...

http://www.quarterbore.com/images/car10h.jpg
Top A2: Bottom CAR

http://www.quarterbore.com/images/car10j.jpg
Left A2: Right CAR

http://www.quarterbore.com/images/car10k.jpg
Left A2: Right CAR

The Buffer

The new buffer that came with the Armalite stock is nearly identical in shape and size to an AR-15 CAR buffer be it the standard 223, H-Buffer, or 9mm Buffer! The big difference is the weight of the buffers and following are some approximate weights:

The Armalite Buffer from the AR-10 CAR stock: 5.3 OZ
A Standard CAR Buffer weighs about 2.7 OZ
The Colt H-Buffer weights about 3.4 OZ
RRA 9mm buffer weights about 5.47oz

http://www.quarterbore.com/images/car10_a.jpg
Top: RRA 223 Buffer - Bottom Armalite AR-10 Buffer

So, going back to the pics and details I posed above, it seems that Armalite thinks that using a standard AR-10 buffer spring with what apears to be the size of the CAR Buffer with a slightly longer internal dimension CAR buffer tube is all that is needed to make a CAR-10.

After I pulled together the review that is summarized above Slash of AR15.com forums got busy and worked up a replacement buffer for the AR-10. What is unique about Slash's solution is that he made his buffers 3/4 of an inch shorter so that with the use of his buffer you could use a standard AR-15 CAR stock, buffer tube, and AR-10 A2 spring to convert your AR-10 to a CAR-10.

Following is a photo of Slash's Buffers:
http://photos.ar15.com/ImageGallery/...ImageUnq=30943

Here is a thread where Slash describes these buffers...
http://ar15.com/forums/topic.html?b=...0&t=229073

Note, I am using the factory Armalite stock but Slash's solution looks like a good solution as well!

I have found that even with a much shorter buffer and buffer srpind my rifle still holds it's groupings very well (unlike many people say) I personally like using a tele stock instead of the normaly issue solid stock