Question about buffer tubes

[NateIU10]

So I just piked up my CMMG bargain bin rifle, and I have a question about the buffer tube. It was slanted, so I assumed it was commercial, but I believe I may be wrong. A bunch of people online said that CMMG uses mil-spec tubes with a commercial length buffer. Can anyone confirm this for me? I'm pretty mad becaseu I just bought a CTR online but it is for commercial, so that'd suck if it doesn't fit.

Thanks

[cmwhitt]

My bargain bin rifle was a DPMS lower....commercial tube (I have a commercial CTR on it).

Which lower is yours?

[NateIU10]

Would a commercial buttstock fit on a mil-spec tube? It should just be a tad loose right? God this sucks :(

[NateIU10]

Mines a CMMG lower. Not a nick on it and I like the rifle rollmark :) And thats good to hear, so either way it should fit :)

[USMC79to83]

There is a difference in diameter between the two - this will allow you to tell which you have...

http://www.magpul.com/pdfs/technotes/ctr/buffertubeid.pdf

[Onmilo]

Get your dial calipers or 2 inch micrometer out.
Military specification buffer tubes run 1.15" +or- .005"
Commercial tube diameter is set at nominal 1.17" with variations all the way down to mil-spec diameter and up to 1.2" diameter.

Easy way to tell a military specification tube are the machined threads that are flattened for three or four threads at the back of the tube and also almost all military specification tubes are four position, not six.
Vltor uses a five position military specification tube diameter.

A military specification stock will fit on a commercial extension tube and is usually pretty loose and sloppy.
Military specification tele-stocks almost never fit commercial tubes because the internal through hole diameter is too small.

[deMontacute]

Easy way to tell a military specification tube are the machined threads that are flattened for three or four threads at the back of the tube and also almost all military specification tubes are four position, not six.Vltor uses a five position military specification tube diameter.
Not true. Older CAR stocks are 4 position. "Mil-Spec" buffer tubes offered by most major manufacturers are 6 pos...

[NateIU10]

CMMG ended up telling me that they used both types in their Bargain Bins, and how to identify which one I had. Looks like I ordered right, I think lol. We'll see when it gets here :dunno: