I am curious: what are the holes and square cuts in the wrench used for? Or to put it this way, do they serve a purpose?
I bought the wrench because I needed on to put the stock assembly on my build. It is a carbine stock wrench, and I have had it for a while. But every time I look at it I just wonder at what the holes and square cuts are for because it looks like they would serve a purpose of some kind.
Edited to add picture of other side
flash hiders on the square cuts
the square hole at the one end by the barrel nut end is for your torque wrench / 1/2" drive / breaker bar
Holy crap!
This could not have been more timely.
Was literally just looking at them on the Sportsman’s Guide site.
Square hole should be 1/2" square and is for a torque wrench or breaker bar.
Square notches should fit flash suppressor and, I believe, receiver extension tube for a fixed stock.
No idea if the round holes do anything or not.
Could you do me a favor?
Please post a picture of the other side of the wrench.
Greg
Yes I can post a picture of the other side.
Thanks for the responses! I have been wondering about this for almost a year.
Edit
Picture of other side up in original post.
Thanks.
Do the serrations on the back side match up with the teeth on the barrel nut?
That is really what I was wondering when asked for the other pic.
Thought I might be able to tell better, but… It sure looks like they should.
Sometimes it just pays to ask the real question.
Don’t tell my buddy Pete I said that.
Having a single multi-tool absolutely sucks in comparison to having the individual components.
You may end up spending a few dollars more, but the difference is huge.
(Besides, you’ve got $1k+ wrapped up into your rifle, are you really going to get cheap on dropping the extra $10-20 on the better tools to work on your rifle?)
&
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=16882&title=AR-15%20M4%20STOCK%20WRENCH
FTMFW.
ETA: I’ve also found DPMS’ “Panther Claw” action block to be the most versatile also:
http://dpmsinc.com/store/products/?prod=1675
Can work with more rails & receivers and doesn’t mark them up.
FWIW- I use the armorer wrench from Guntec USA and it’s probably the best I have used and much better than the standard G.I wrench. One critic about those RR buttstock wrenches from Brownells is that they are not real solid. If you get a castle nut that has been welded on by some idiot with Loc-Tite or Rocksett it will be a PITA.
Would that be this one?
http://www.tacticalgears.com/scripts/prodView.asp?idproduct=39
That looks like the one.
Run away.
That’s the same Guntec that hocks Chinese Airsoft crap at gunshows, do a search for the rest of their products on that site.
In addition to the one I had, I’ve seen other multi-tools of theirs be so grossly out of spec as to ruin parts. The stock wrench portion of that “tool” is too obtuse (?) so that the lone tooth can’t quite grab onto the lock nut (Hello stripped lock nut).
Also, on the barrel nut side, the three little noodle-like teeth that grab into nut were all all going in different directions and wouldn’t even index properly onto the nut.
The A2 stock screwdriver tip however worked flawlessly. 
I think I traded it away for a pint of beer, and I feel I got the better end of the bargain. Let me see if I can snap some pictures of it this afternoon.
Sorry I have no experience in that regard, so, I cannot tell you if they do or not. I got it so I can assemble the stock. I have yet to assemble my lower at the moment, but this is the first one I will have done. I have not built an upper receiver. I thought about it, but I decided to just acquire a LaRue 16" complete upper this time.
Cool.
I may be a noob to getting down and technical. I posted this out of curiosity. Perhaps a comparison to all the wrenches is in order. I noticed some were discussing how the DPMS wrench breaks, which is actually what got me wondering about the Bushmaster wrench I own.
If that is the case I am cool with retitling the thread moderators, and then making a sticky so others know about the different wrenches that exist as well as their various functions. I say that because I never knew this was so indepth.
Yeah I know I am bringing back an old thread.,…
Anyone buy one of these wrenches form ebay? It is a little different than the originally posted wrench…has an extra tool on it.
I need to get one of these for my AR build…should I just stick to the one at Model1Sales?
These are cheap Chinese or Taiwan made wrenches. My neighbor has one that looks exactly like it. I would steer clear.