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AR15.COM
4/29/2009 10:51:29 AM EDT
Hey guys
I bought a commercial Magpul CTR stock for my AR. The buffer tube is off a Bushy and the tube has a slanted back. I don't have calipers to accurately measure the back of the tube. Everything I have read says MOST of the time a slanted back or a Bushmaster tube should be commercial.

So here is my problem. The friction lock doesn't do anything. It feels the same locked up or unlocked. I have slop either way. Is there any way to adjust it or is my tube a mil spec?

Thanks
Ty
4/29/2009 10:01:54 AM EDT
[#1]
Sounds like it must be a milspec then.
4/29/2009 10:12:54 AM EDT
[#2]
Quoted:
Sounds like it must be a milspec then.


It is not, Bushmaster uses commercial receiver extensions.

The problem is the many different minor variations in receiver extensions from different manufacturers, in my experience this occurs in both commercial and mil-spec. A friend bought a Del-ton kit, it has a commercial extension and the CTR still moves ever so slightly when locked. I had a CMT mil-spec extension on my carbine, and my mil-spec CTR still moved slightly forward and back when locked. I replaced the CMT extension with a complete BCM stock mounting kit and the same CTR now locks up as tight as a bank vault.
4/29/2009 10:25:59 AM EDT
[#3]
That's kinda what I figured. I have no problem buying a completely new buffer tube, spring and buffer. Any suggestion on which commercial buffer tube locks up tight with a CTR?
4/29/2009 10:30:52 AM EDT
[#4]
Quoted:
That's kinda what I figured. I have no problem buying a completely new buffer tube, spring and buffer. Any suggestion on which commercial buffer tube locks up tight with a CTR?


Honestly, it is going to be a crap shoot.

I can tell you with 100% certainty my mil-spec CTR locks up without the slightest bit of movement (no exaggeration) on the BCM extension. Maybe you should hock your commercial CTR on the EE, grab a BCM mounting kit and mil-spec CTR?
4/29/2009 10:32:23 AM EDT
[#5]
My experiance was the exact same with the CTR on my milspec Colt. I sold it and went back to my original OEM stock. I don't drink the Magpul Kool Aid as many here do. Flame suit on.....
4/29/2009 10:34:10 AM EDT
[#6]
Quoted:
That's kinda what I figured. I have no problem buying a completely new buffer tube, spring and buffer. Any suggestion on which commercial buffer tube locks up tight with a CTR?


The spring and buffer should be the same for both mil-spec and commercial tubes, and the castle nut should be the same too (somebody correct me if I'm wrong here.)  Perhaps return the commercial CTR for a mil-spec, and buy a mil-spec tube.
4/29/2009 10:36:02 AM EDT
[#7]
Quoted:
Quoted:
That's kinda what I figured. I have no problem buying a completely new buffer tube, spring and buffer. Any suggestion on which commercial buffer tube locks up tight with a CTR?


The spring and buffer should be the same for both mil-spec and commercial tubes (somebody correct me if I'm wrong here.)  Perhaps return the commercial CTR for a mil-spec, and buy a mil-spec tube.


This is true, but I noticed the CMT spring almost appeared to be coated while the BCM spring was clearly stainless steel, so that was another plus for me.  I e-mailed Bravo Company and was told their carbine action spring is based on the Colt LE6920. Also, it would be a good opportunity to upgrade to an H buffer while he is at it. Win/win.
4/29/2009 10:36:36 AM EDT
[#8]
Yeah I know they are the same but I wanna use the whole thing with my other stock for a different lower.

Damn I guess I'll take this thing back and try the mil-spec.
4/29/2009 10:43:24 AM EDT
[#9]
AIM has CMMG 5 pos. Mil spec tube kits in stock for $59.95.
4/29/2009 11:05:51 AM EDT
[#10]
Just helped a friend put his gun together and he bought a commercial CTR and the Commercial tube kit from PK and it locks up very tight.  You really don't need the whole kit...but if you were to buy the whole kit that would leave you with your standard 6-pos stock and tube/Spring/buffer/nut and plate for another build in the future.

Here is the one my friend bought.

http://www.pkfirearms.com/select_options/new/295

ETA....It would be to your advantage to upgrade to the H buffer if you buy this kit.  It really helps on recoil for getting back on target quickly.
4/29/2009 1:39:21 PM EDT
[#11]
What I did was knock the roll pin out of the friciton lock.  Inside you will find a metal piece that is in a "U" shape.  Take a pair of pliers and ever so slightly, squeeze it closed a tiny bit.  Put it back together and try the friction lock again.  You only need to squeeze it a little bit to make a big difference.
4/29/2009 1:47:47 PM EDT
[#12]
Quoted:
What I did was knock the roll pin out of the friciton lock.  Inside you will find a metal piece that is in a "U" shape.  Take a pair of pliers and ever so slightly, squeeze it closed a tiny bit.  Put it back together and try the friction lock again.  You only need to squeeze it a little bit to make a big difference.


THIS is your answer. Try this before you buy anything or return anything.

I had to do the same thing with my Bushmaster tube.
5/2/2009 9:10:47 AM EDT
[#13]
This answer fixed my problem. Take out the roll pin like he says. Pry up the metal piece a bit and squeeze with pliers.

Thanks!
5/2/2009 1:46:47 PM EDT
[#14]
Good ending.  

The issue is there is no true spec. for comm. tubes.  We have designed the CTR comm. off of all of the comm. tubes we could get our hands on.  Try measuring the tolerance on multiple comm. tubes.  Far cry from all being the same or even close.  Try the same with Milspec.  They'll all be pretty darn tight as far as specs.  YMMV.  This is my experience.  

Comm spec tubes funtion in my use as as the same as Milspec.  The friction lock may not perform to it's optimal level though.  Glad the fix worked for you.

Cheers.
5/2/2009 9:56:25 PM EDT
[#15]
Quoted:
Good ending.  

The issue is there is no true spec. for comm. tubes.  We have designed the CTR comm. off of all of the comm. tubes we could get our hands on.  Try measuring the tolerance on multiple comm. tubes.  Far cry from all being the same or even close.  Try the same with Milspec.  They'll all be pretty darn tight as far as specs.  YMMV.  This is my experience.  

Comm spec tubes funtion in my use as as the same as Milspec.  The friction lock may not perform to it's optimal level though.  Glad the fix worked for you.

Cheers.


So what you are saying is I was correct.
5/11/2009 7:23:35 PM EDT
[#16]
Be VERY  careful with this fix. I did it and busted the little clip. hopefully magpul can get me a replacement quick. maybe should order two just in case
5/12/2009 5:48:15 AM EDT
[#17]
Quoted:
Be VERY  careful with this fix. I did it and busted the little clip. hopefully magpul can get me a replacement quick. maybe should order two just in case


Jesus Christ why do people have such a difficult time? First we have a couple of guys torquing the shit out of their MBUS screws, breaking the damn things. Then you come and say you snapped the fucking clip in half? You are supposed to tweak it, not crush it!

6/1/2009 5:27:19 PM EDT
[#18]
I have the same problem, kind of. I had a black commercial CTR that fit perfect on my Bushmaster extension. My friend wanted a black CTR, and I wanted to swap out for a FDE, so he bought a new commercial FDE and we swapped.  Lo and behold, the FDE one rattles, and doesn't lock up tight.

Any ideas? Might get some punches tomorrow and try the friction lock fix.

Gratuitous pic of pre-rattle days:
http://www.reddynasty.com/pictures/rifle_after.jpg
6/1/2009 7:12:19 PM EDT
[#19]
Quoted:
I have the same problem, kind of. I had a black commercial CTR that fit perfect on my Bushmaster extension. My friend wanted a black CTR, and I wanted to swap out for a FDE, so he bought a new commercial FDE and we swapped.  Lo and behold, the FDE one rattles, and doesn't lock up tight.

Any ideas? Might get some punches tomorrow and try the friction lock fix.

Gratuitous pic of pre-rattle days:
http://www.reddynasty.com/pictures/rifle_after.jpg


My guess is that we would suggest you try the fix that has been discussed in this thread.
6/2/2009 7:18:40 AM EDT
[#20]
Quoted:
My experiance was the exact same with the CTR on my milspec Colt. I sold it and went back to my original OEM stock. I don't drink the Magpul Kool Aid as many here do. Flame suit on.....


My CTR was sloppy on a vltor milspec tube so I'm right there with you. I think the design was nice LOP all that but I've gone with vltor emods or modstocks for my rifles as of now.

Sometimes things work well with your rifle and other times no matter how bad you want it to they just don't fit well.
6/2/2009 11:53:02 AM EDT
[#21]
Quoted:
Quoted:
My experiance was the exact same with the CTR on my milspec Colt. I sold it and went back to my original OEM stock. I don't drink the Magpul Kool Aid as many here do. Flame suit on.....


My CTR was sloppy on a vltor milspec tube so I'm right there with you. I think the design was nice LOP all that but I've gone with vltor emods or modstocks for my rifles as of now.

Sometimes things work well with your rifle and other times no matter how bad you want it to they just don't fit well.


Or you could try the fix mentioned in this thread.  Or not.  

These are mechanical problems, there are answers to them, it isn't a fluid problem where the variables are always changing.
6/2/2009 12:52:30 PM EDT
[#22]
Commercial tubes have no "true spec" period.
6/2/2009 1:05:18 PM EDT
[#23]
I tried the fix listed above without success. As a result I turned to the trusty roll of duct tape. I cut a 1"x2" rectangle and inserted it in the channel over the friction lock. The result is a CTR that locks solid. I know most won't like this idea but it works and you can't see the duct tape.
8/3/2009 9:44:57 AM EDT
[#24]
I tried and failed also.  I got it to tighten up 0.010" and it still wasn't tight enough to make a difference. So I go for another 0.005" and it sounded like a mini Garand after the 8th shot.






8/3/2009 10:05:00 AM EDT
[#25]
Quoted:
I tried and failed also.  I got it to tighten up 0.010" and it still wasn't tight enough to make a difference. So I go for another 0.005" and it sounded like a mini Garand after the 8th shot.


http://i213.photobucket.com/albums/cc183/mschw04/DSC00027.jpg


Email Justin or call them, I'm sure they'll take care of you.
8/3/2009 10:07:38 AM EDT
[#26]


Thanks,



I'll do that in a few days.  For now... I'm off to the range for an overnighter






8/26/2009 11:58:13 AM EDT
[#27]




Quoted:



Quoted:

I tried and failed also. I got it to tighten up 0.010" and it still wasn't tight enough to make a difference. So I go for another 0.005" and it sounded like a mini Garand after the 8th shot.





http://i213.photobucket.com/albums/cc183/mschw04/DSC00027.jpg




Email Justin or call them, I'm sure they'll take care of you.


I did both.  Generally speaking.... any idea how many weeks it takes to get a response?  It's been 3 weeks on the email and 2 weeks on the voice mail and I haven't heard back from them.  



8/26/2009 12:32:06 PM EDT
[#28]
It's difficult to run down mil-spec buffer tubes from one place, and CTR'S from another.  How about selling only Mil-Spec CTR's with buffer tube included. I'm in for one.
9/20/2009 6:02:52 AM EDT
[#29]
Ok, I have a Bushy ORC and just ordered the CTR commercial.  Should I refuse the package or try this fix?  If I refuse the package, what the hell do I order then?  Will a Millspec tube fit a commercial lower?  What commercial tube does MAGPUL use that they know works???  Amazing that this is not mentioned anywhere on the magpul site.  They need to disclose this and recommend.
9/20/2009 6:23:09 AM EDT
[#30]
I got one last year, the commercial and it fit my bushy perfectly, no movement
9/20/2009 9:12:55 AM EDT
[#31]
Hi mike, what model bushy?  I may just wait and see if it works....
9/20/2009 9:22:14 AM EDT
[#32]
carbon 15, I was under the assumption that all bushmasters were commercial as the commercial magpul cost me more money, thats why I remember what it is.

9/20/2009 10:15:32 AM EDT
[#33]
well hopefully I will have the same luck.  I wonder why the Original poster had issues being it was a Bushy tube?
9/20/2009 3:00:24 PM EDT
[#34]
Quoted:
Ok, I have a Bushy ORC and just ordered the CTR commercial.  Should I refuse the package or try this fix?  If I refuse the package, what the hell do I order then?  Will a Millspec tube fit a commercial lower?  What commercial tube does MAGPUL use that they know works???  Amazing that this is not mentioned anywhere on the magpul site.  They need to disclose this and recommend.


Unlike receiver extensions, there is no such thing as a "commercial lower." Your lower is in-spec or not. Most companies get their lowers forged from the same company, anyway.

To answer your question–– yes, your lower should accept a "mil-spec" tube with no issues.
10/12/2009 4:47:14 PM EDT
[#35]
2 month bump - still waiting
10/12/2009 6:10:29 PM EDT
[#36]
If any are looking for a commercial tube that will work for sure, I got one from PKfirearms.  It slides very tight, and locks up super tight.
10/13/2009 8:06:39 AM EDT
[#37]
Sorry I'm late to the party here but I'll try to clarify a few things:
-  Both mil-spec and commercial-spec receiver extension tubes DO vary between manufacturers and sometimes with the same manufacturer over different years.  I honestly can't say whether mil-spec tubes are more consistent than commercial-spec as I've seen both with tolerances all over the place.
-  Bushmaster uses commerical-spec from what we've seen but I can't comment on the Carbon 15 series.
-  The CTR Friction Lock cannot do much for fore and aft movement.  Being that it clamps on to the lower rail it will do an admirable job of minimizing rotational movement and general wobble on a good tube, but it can only control fore/aft movement via friction (which is more dependent on wear to the Friction Lock pads, any oil present, surface finish of the tube, etc.)  This fore/aft play is really a function of the crummy Colt design of the CAR locking mechanism and its single-sheer pin that all M4 carbine stocks are saddled with (which is why we abandoned it in favor of a far superior latching mechanism for the UBR).
-  The steel Friction Lock plate is hardened after forming and is therefore fairly easy to break by squeezing it in a vice- it is not very flexible.  If you do attempt it please be gentle...

Regarding response times, while email can sometimes take us a number of days to respond to (I go through nearly 5000 emails in any given three month period), voicemails get taken care of within a day or two in most all cases.  ASSUMING we actually receive either one.  We get a ton of voicemails where people do not give a return phone number, the number or message given is unintelligible, or no one answers when we call back (no voicemail?!).  Also, we regularly check our junk mail boxes but if an email doesn't make it there or in to our inboxes then we'll never know it was sent- remember, email is not infallible.  This industry is very busy right now and Magpul happens to be one of the more popular companies to boot.  Point being, if you do not get a response from us within a few days then you can assume that we either never got your inquiry or you never got our response.  Be persistent, try another method of contacting us, and we will get back to you as soon as we possibly can.