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Posted: 10/13/2006 3:04:22 AM EDT
| Why the hell do companies make buffer tubes different sizes? That makes no sense. I see some stock advertised as fitting "Colt tubes only", etc. WTF. |
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The non-mil-spec tubes are made of cheaper construction. The threads are pressed into the tube, the tube is usually of lower quality and the endcap may or may not be welded on. It's all about cost savings, as are most AR15 related problems. You get what you pay for. Buy accordingly. In spec tubes: Colt LMT CMT/Stag VLTOR And all tubes made by or for those companies and sold under other names. Note that my list is not inclusive. |
I don't have the pictures. I have seen them posted in the AR board though. Basically on Mil-Spec tubes the threads come out of the body of the tube. On the others, they are indented. Receiver extensions are aluminum. I do not know which specific material is proper though. |
I researched the subject years ago when making my personal buying decisions. Would be happy to duplicate the research for you for my normal consulting fee, if you'd like. The free answer is what I remember: Colt milspec= good stuff, aftermarket non milspec tubes=junk. It had to do with not only materials, but thread size, tube size, finish, and heat treat. |
Soooooo, do you happen to remember what is the failure mode for these so-called junk tubes? Do they snap in half? I'm still waiting for both of mine to fail. |
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If you are truly interested in a quality product, start your research with "thread class" and "thread fit". Also, see the troubleshooting forum re "my buffer retainer popped out". There is a market for cheap gun parts, just like there is a market for high quality gun parts, but it isn't the same market. |
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Could just start calling mil-spec tubes their proper name; receiver extensions. While continuing to call the commercial ones buffer tubes. I wouldn't consider a commercial tube a receiver extension; no way I'd want to try and clear a stuck case using the "smack the ground" method with a "buffer tube." |
Yes! They'll break. If you never drop your rifle, you'll probably be ok. Some nut on this site did a test to see if some optic would hold zero. He was doing a drop test on his own gun. He ended up breaking the MIAD grip and the NON spec buffer tube. Broke the shit right off the weapon. I saw the pics. |
These things happen! |
My 15 lb RRA NM fell off a table the other day. Buttstock is still attached. Quality is quality, whether it meets Colt's blueprints or not. There's more than one way to skin the cat. |
The one that fell was a rifle stock. I have a carbine too, with a POS non mil spec tube. Haven't given it enough hard use to tell. The link to M4C.net was not useful. The description of the threading methods was not understandable to someone looking to make an informed decision on solid technical grounds. You could start by describing the exact size and type of threads in Colt's BP and those most commonly used by the non-mil-spec mfgrs. Maybe I'll look it up myself later. |
that was the guy testing the durability of some CHICOM hippie red dot scope to prove that his support of communism and the demise of the free world was well worth $50.  instead of breaking the SPOT DOT/TACPOINT/GI JOE Action Extreme RDS, he broke his rifle. IIRC he was tossing the thing up like 20ft into the air and letting it smash onto the ground. 
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Non-milspec tubes start with a tube of a certain diameter and roll the threads into it. That is why their OD is larger than mil-spec tubes and stocks for mil-spec tubes won't fit. Mil-spec tubes start with a forged or extruded tube of the proper diameter and cut the threads into them. Not exactly sure of the process, but non-milspec tubes are made the way they are purely as a cost-saving measure. They work fine for most purposes, though. |
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The commercial-diameter receiver extension made by RRA are made from an extrusion as well. The material we use is the same as the spec diameter tubes, as is the manufacturing process, as is the mil-spec finish on them. The only significant difference is the outside diameter of the rear portion of the tube, and how the thread is created. The mil diameter tubes are are made from a smaller diameter extrusion and their thread is displaced outward from the metal of the extrusion, which results in the thread OD being larger than the diameter of the tube. The commercial tubes start with a larger diameter and machine the thread into the extrusion, leaving the OD of the thread the same as that of the tube. Steve/RRA |
Thanks Steve. I fail to see how a non-mil spec tube made your way is weaker than a mil-spec one. In fact, it may even be stronger since the thread minor and major diameters are the same as mil-spec, but the wall thickness is greater for the whole length. As usual, it takes some work to sift through the non-technical kool-aid drinking nonsense around. |
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The thread diameter is the same on both "mil-spec" and "commercial" receiver extentions. The body diameter is smaller on the "mil-spec" extentions than on the "commercial." That's a simple as I can explain it. Whether or not a particular "commercial" extention is stronger or weaker than a "mil-spec" diameter one, I would expect to be a function of materials and construction, more than the outside diameter. Not having that data, I will not venture an opinion, being a simple Armchair Commando.  Lonny |
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