mil spec/commercial buffer tube question

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Both the milspec diameter (1.148") and commercial diameter (1.168") receiver extension can be screwed into a milspec lower receiver. Do you have any way to measure the diameter? Or test your existing stock on a known size tube?

And btw, a New Frontier lower is anything BUT milspec. And I suspect it uses a commercial diameter tube but be sure before ordering. A commercial stock will be very sloppy on a milspec tube, a milspec stock won't fit on a commercial tube.
 
nah man, everyone has it in their head that NFA guns are some kinda gimmick or substandard or something because they make those polymer lowers. I have no experience with them and can't really comment but I know that my rifle (a G-15 G-TAC) is pretty damn nice. Had a few feed issues at first, but now that the buffer spring is broke in and I have a few lubrication tips, it functions flawlessly. About 1000 rounds without failing to cycle now. They use all YHM metal and I've added a lot of magpul stuff to it, so it's outfitted fairly well. I'm a lefty so I've installed a left handed mag release and safety selector. I have one of those DPMS oversized dual paddles on the way. I don't have a problem with the paddle as it is so I just want it to make it easier to lock the bolt back.

The last thing I need is a stock. I'll measure it tomorrow. Thanks for the link!
 
A mil spec lower means nothing as to what tube is installed. Threads are the same. As Quentin said, it's the tube diameter after the threads that is different (usually rounded to 1.15" & 1.17"). As well, mil spec tubes are usually 7075 alloy, commercial are typically a softer 6061. Of course, commercials are also thicker.

Either type can be 4, 5 or 6 position.

Mil spec or commercial tubes only affect stock fitment. A mil spec stock will not go on a commercial tube (not without a hammer, anyway), and a commercial stock will be very sloppy on a mil spec tube (can be made tight with electrical tape).
 
There is no such thing as a "Mil-Spec" commercial lower anymore.
Don't care what material it is made from or what finish is applied, commercial lowers are not machined to accept the auto sear nor are they drilled to accept the securing pin.
There are "Mil-Close" commercial lowers, there are no "Mil-Spec" commercial lowers.
That said, "Mil-Spec" extension Tubes tend to be made of better materials that commercial extension tubes.
A1 & A2 fixed stock military specification extension tubes are also made of 7075 aluminum alloy and there are cheap versions of these standard size tubes floating around as well.
 
commercial lowers are not machined to accept the auto sear nor are they drilled to accept the securing pin.
There are "Mil-Close" commercial lowers, there are no "Mil-Spec" commercial lowers.
Click to expand...

I can't argue with this.

For all intents and purposes, though, I would consider any 7075-T6 forged receiver capable of accepting standard parts to be mil spec. I think most would agree. For the purposes of title I ARs, a non-mil spec lower would be one that uses proprietary parts.
 
Onmilo expressed it exactly. If you don't mindI want to borrow he "mil-close" phrase. Like these other guys said the only way to know about the tube is to measure it. Let us know what you find..
 
If you remove the tube from the lower, the commercial tube will have the threads cut into the tube with the major diameter the same as the tube body, while the mi-spec tube has the threads raised above the major diameter of the body. The commercial tubes also usually, but not always, have the rear face of the tube cut at an angle while the mi-spec are square.
 
while onmillo was technically accurate, the way he wrote it implies that the 'mil-spec' is a monolith rather than a collection of hundreds of requirements, and that we are not bright enough to discern the desirable features of 'mil-spec' for a civilian, from the undesirable ones. As if by throwing out the full-auto switch, all the rest of the specifications are somehow meaningless.

further, you can buy a mil-spec receiver extension, which is the subject of this topic, even if you can't get a recently manufactured, full-auto complete lower
 
while onmillo was technically accurate, the way he wrote it implies that the 'mil-spec' is a monolith rather than a collection of hundreds of requirements, and that we are not bright enough to discern the desirable features of 'mil-spec' for a civilian, from the undesirable ones. As if by throwing out the full-auto switch, all the rest of the specifications are somehow meaningless.

further, you can buy a mil-spec receiver extension, which is the subject of this topic, even if you can't get a recently manufactured, full-auto complete lower
 
True, there is no civie ar15 that is true milspec, but i would suggest getting as much milspec as possible.
 
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