Comm buffer tube VS. Mil spec tube? - Shooting Sports Forum


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Old 10-07-2009, 18:52   #1
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Comm buffer tube VS. Mil spec tube?

i realize theres a diameter difference the comm tube being 1.17" and the mil spec being 1.14". But is there a difference in quality? I cant find any information that would have me believe one is better than the other nor can I see difference in quality between the two..

Reason I would like to know is because I currently have a tapco T6 stock on my carbine. But wanted to upgrade to a CTR stock but if I'm gonna dish out 95 clams would it be better to invest in a mil spec tube aswell instead of just getting a comm CTR stock? this then brings up another question if the mil spec tube is better and I buy a mil spec tube and CTR stock will the buffer and spring from my comm tapco T6 work in a mil spec tube??

why I question this is because from my experience Mil spec only means it meets a guideline set by the military as spec but doesn't necessarily mean its better or right. Just a guideline set mainly to keep logistics and parts interchangeability simple.

Some have said the mil spec tubes are forged and the comm tubes are drawn and the comm tubes are larger diameter because drawn aluminum is supposedly weaker than forged. I dont really buy that.... because asfar as I can tell both appear to be drawn aluminum. thanks
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Old 10-07-2009, 20:06   #2
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DPMS ships it's ARs with commercial tubes. There are a couple of others, but that's one that stuck in my mind as I had one. I did not find any difference in quality between that and the milspec ones I bought separately. Buffers are the same in both, and the springs as well, as far as I could see.

Jim
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Old 10-10-2009, 06:48   #3
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Buffer tubes are cheap and the commercial tubes are readily available as well as stocks. I would stick with the commercial tube. It also isn't one of the parts prone to break.
I never really understand the reason for 2 sizes. Anyone know why?
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Old 10-10-2009, 08:55   #4
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There seems to be more stocks for the milspec tubes thant commercial, but if you find the stock you want in commercial, I'd just leave it alone and get the commercial stock.

Jim
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Old 10-11-2009, 09:25   #5
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I didn't know there were two different types of buffer tubes/stocks until I had already bought one. Turns out it was a commercial style stock. When I screwed the tube into the receiver it seemed like the fit was real loose and sloppy. That led to a lot of reading which led me to the info I wish I'd had before buying. I'll have to go back and do some research to find the article. It said that sometimes the commercial tubes would strip the threads out or break the the receiver where the tube screws in ruining the receiver. That in itself got my upset...... so I'll be ordering a milspec buffer tube soonest. Why? Just because the though of that kind of failure is not acceptable.
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Old 10-11-2009, 09:57   #6
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Rutro,

Where did you read that? I had a lower with a commercial tube, and didn't notice any slop.

Jim
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Old 10-11-2009, 16:14   #7
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I'm pretty sure it was on AR15.com. But there is so much info there to go through it may take a while to find it.
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Old 10-11-2009, 16:47   #8
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Here is the same info I just found on M4Carbine.net
This is a quote from K.L. Davis. This is a link to the thread, http://www.m4carbine.net/showthread....al+buffer+tube, good info!!!


Buffer Tube Basics
I know, the correct name is receiver extension tube... so now that we got one of most common mistakes out of the way, let's look at some common questions about receiver extension tubes. I do not pretend to know everything about these rifles, so if you see anything that is wrong, let me know.

This info is for carbine/short/collapsable tubes - all rifle/long/standard tubes are the same (as far as dimensions go)

What is a Mil-Spec Tube? This has to be the most common question. A milspec tube is just as the name implies, made to the specifications of the technical data package (tdp). The biggest concern is the diameter of the tube, the milspec part has a diameter of ~1.147, the thread diameter is 1.1875

So the threads are bigger, are they rolled in? originally the threads were cut in with a regular old lathe. The narrower body section of the tube is reduced by cutting with a concave shaped cutter that "shaves" the metal down, sort of like a plane; occasionally you can see the result of this technique by two "lines" that run the length of the reduced section at ten and two o'clock. Current techniques do include rolling the threads in.

So what are tubes that are not Mil-Spec? During the original cloning of the military AR, the first commercial receiver extension tubes were made from an extrusion, the threads lathe cut and the body was not reduced. The common size for this is 1.170 and that has became the de facto standard for after market tubes.

So commercial tubes are bigger, are they stronger? No, the problem with them is that the threaded section is also 1.170, so the threads are not cut to full "height" and do not fully engage the threads in the receiver. The few commercial tubes that I have seen fail, pulled the threads out of the receiver.

Are there any other concerns with after market tubes? Well, there is really no set standard for size, so they can vary by manufacturer and even from lot to lot -- you can get combinations of after market parts that are tight or loose. Some of them are made with extrusions with an end plug welded in, the quality of the welding can run from pretty solid to pretty poor.

Are those the only two sizes? No, some manufacturers have come out with systems that do not use either the milspec or the aftermarket tube size... The early Choate stock is one example of a proprietory tube.

So what fits what? Milspec tubes work with stocks from Colt, Vltor, CMT, LMT/Crane, etc.

After market tubes work with RRA, BM, DPMS, etc.

A larger, after market stock will fit on a milspec tube, but will be loose and rattle -- a milsec stock will usually not fit on an after market tube... without a hammer.

Hey! My new Mil-Spec tube is too long? Some newer tubes made for the "enhanced" M4 stock are a little longer and have a small taper to the back to match the profile of the stock butt. It should not effect the use of a Mil-Spec stock however.
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Old 10-13-2009, 00:08   #9
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good info there!
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Old 10-13-2009, 08:24   #10
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Where can I find the best priced Carbine 6 position buffer tube, spring and buffer? I need to buy two sets. I was thinking about just going through local DPMS dealer.
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Old 10-13-2009, 08:30   #11
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Originally Posted by DrewArtist View Post
Where can I find the best priced Carbine 6 position buffer tube, spring and buffer? I need to buy two sets. I was thinking about just going through local DPMS dealer.
DPMS uses commercial sized tubes. http://www.palmettostatearmory.com/429.php for a milspec one, they're good people to work with.

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Old 10-13-2009, 08:33   #12
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Hey thanks Jim. I don't need the stock, just tube and accessories, but I see that they sell tubes as well.
http://www.palmettostatearmory.com/408.php
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Old 10-13-2009, 09:02   #13
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I have two of their milspec tube setups, they work great, fit perfectly on both my Spike's and my YHM lowers.

Jim
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Old 10-13-2009, 23:12   #14
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Originally Posted by jimbobborg View Post
DPMS uses commercial sized tubes. http://www.palmettostatearmory.com/429.php for a milspec one, they're good people to work with.

Jim

those arent milspec... thats what I have on my carbine at the moment and the tapco T6 is not mil spec.

I go through bravocompanyusa.com for alot of stuff. they have mil spec receiver extensions for 20 bucks and buffers for like 11 bucks. yo will probably also need the stock ring and nut too dont know what those cost but they have them too.
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Old 11-05-2009, 17:18   #15
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I just ordered a milspec buffer tube from Midway for $16.99 on Monday and got it yesterday. When I screwed it into the receiver the difference was like night and day. I used the buffer and spring that came with the commercial tube along with the nut and receiver end plate. The plate had to be releived a little to go on, took about 5min. worth of file work. With gun shows around here for the next 3 weekends in a row I probably will find another stock.....
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Old 11-06-2009, 14:58   #16
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If you require a carbine stock then get one but..... A full lenghth rifle stock is more reliable. When they shortened the ar to the M4 platform they created a much more violent gas cycle. This is componded by a shorter and lighter buffer. A rifle stock and buffer will slow the cycle a little creating a more reliable action. I have seen fewer extraction issues with a rifle stock aswell.
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Old 11-07-2009, 01:20   #17
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Originally Posted by Zydeco76 View Post
If you require a carbine stock then get one but..... A full lenghth rifle stock is more reliable. When they shortened the ar to the M4 platform they created a much more violent gas cycle. This is componded by a shorter and lighter buffer. A rifle stock and buffer will slow the cycle a little creating a more reliable action. I have seen fewer extraction issues with a rifle stock aswell.

I have a mid length gas system. Cyclic between the two stock styles are no different asfar as I can tell.
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Old 11-07-2009, 09:11   #18
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Originally Posted by Zydeco76 View Post
If you require a carbine stock then get one but..... A full lenghth rifle stock is more reliable. When they shortened the ar to the M4 platform they created a much more violent gas cycle. This is componded by a shorter and lighter buffer. A rifle stock and buffer will slow the cycle a little creating a more reliable action. I have seen fewer extraction issues with a rifle stock aswell.
You can get a heavier carbine buffer, they're about $30. I run a 6.8 SPC carbine and I haven't had any problems, but I've only shot about 300 rounds through it.

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Old 11-07-2009, 15:34   #19
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I run an H2 buffer to slow it down when I use the carbine stock on my M4 clone. However the rifle buffer is still the most reliable option. A mid length gas system is the way to go, however I was refering to the carbine system. If your having extraction issues and have a rifle buffer setup handy try it out before you got buying a wiz bang extractor upgrade.
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