Buffer Tube Differences?

[Ahab]

I have two buffer tubes on my AR15's. One is a RRA 6 pos(Top), with a flush, slanted back to it. The other is (supposedly) an Armalite 4 pos (Bottom).

The black stock came with the RRA slanted-back tube, the green stock came with the Armalite(?) tube.
I measured both tubes and they are within acceptable limits of each other about .010in or less on all dimensions except length. Internal lengths are the same at 7in. Tube dia = 1.165in, rib width .470in - .480in, Length over rib and tube = 1.463in - 1.473in

The Armalite(?) tube, when the stock is fully collapsed, is recessed almost
5/8in into the stock.
Are either one a "Mil Spec" tube, as I am told true Colt tubes are? Is the recessed Armalite tube normal?
What do other people have as far as buffer tubes go?

Thank for any help guys.

Ahab.

 

[mebiuspower]

From the research that I've done, only StagArms and Colt make mil-spec tubes.

Now I know StagArms sell a 6-position tube, does anyone know any dealers selling those in Canada?

 

[sparhawk]

Add LMT and Vltor to the milspec list

 

[Questar]

Unless you want to play with Vltor or Crane, there isn't really an issue. The colt tube is forged. Many "other" brands are extrusion tubes.

I think the slanted tube is RRA's creation because they seem to like to create funky stuff for brand recognition. I could be wrong, I have had two Colt enhanced stock kits that come with the normal tubes, but that was at least 2 years ago.

Not an RRA creation... I have 6 position Tactical stocks from 3 different manufacturers and they all have the slanted tube to match the slant on the back of the stock (this includes the Bushmaster's that just arrived).

 

[KevinB]

Colt, Diemaco/Colt Canada , LMT, KAC, VLTOR make MIL-SPEC tubes