AR 15 Buffer Tubes - 6061 or 7075?

[EssOne]

NOTE: This post refers only to AR 15's chambered for the 5.56mm cartridge.

 

I've seen it written that prolly half of the buffer tubes being made today are made from 6061 aluminum, although the milspec calls for 7075 aluminum. I know for a fact that Palmetto and Anderson are using them and I see a number of other makers advertising the 6061 buffer tubes. In researching the differences from the personal experiences being talked about on the gun forums, about the only real difference I can find in performance is that a lot of guys feel that if one fell on the gun, the 6061 buffer tube would prolly break at the threads, since their threads are cut into the tube, whereas the threads on the 7075 tubes are said to be on the surface, and 6061 is quite a bit weaker than 7075. 6061 is cheaper and easier on cutting tools, and, as I just said, it is a weaker metal than 7075, but I can't find any evidence of failures in service.

 

Does anybody know of any 6061 buffer tubes that have failed to give proper service in non-abusive usage? Any other drawbacks you can see with them?

 

EssOne

Edited July 9, 2015 by EssOne

[btq96r]

The way I had it explained to me, is mil-spec calls for a harder material on the buffer tube because you're taught to you use the butt of your rifle to control your fall at the end of a 3-5 second rush during contact drills.  It wasn't a big a deal with the large buttstock of an M16, but with the M4, you need to make sure that part is sturdy.

 

Unless you're in a very intensive shooting course, 6061 should be more than fine for civilian use.

Edited July 9, 2015 by btq96r

[Oh Shoot]

.... the 6061 buffer tube would prolly break at the threads, since their threads are cut into the tube, whereas the threads on the 7075 tubes are said to be on the surface

 

As far as the threads, it's my understanding the cut vs extruded has nothing to do with the type of aluminum, but only the diff between milspec and commercial spec.

 

Commercial starts with larger diameter tube and cuts the threads, while milspec starts with smaller diameter and extrudes the threads.

 

There are lots of "milspec" tubes that don't use 7075, as that term is really de facto used to designate the diameter of the tube rather than the composition of it.

 

- OS

Edited July 9, 2015 by Oh Shoot

[EssOne]

Unfortunately there is a lot of misinformation out there on the subject, which is why I'm asking here. One site says Milspec is made out of 7075 and the Commercial tubes are made out of 6061, while another authority says basically what you said, that the diameter of the tube alone determines if it is milspec or not, regardless of the metal used. Then the different seller sites use anything but standardized terminology, which defies a confident conclusion of the issue.

[Ted S.]

Whatever's cheaper. Milspec könne mein Arsch küssen.

Sent from my SAMSUNG-SGH-I547 using Tapatalk

[Garufa]

"Milspec" as in what the US military requires are tubes made out of 7075 material with specific threading and dimensions.  There are plenty of "milspec" tubes out there that are not made of 7075 but satisfy the dimensional requirements.

 

It's really not something to get all bent over as the term "milspec" is way over used and very few civilians have 100% milspec weapons....for the sole reason there's that pesky little selective fire requirement.

Edited July 9, 2015 by Garufa

[Oh Shoot]

"Milspec" as in what the US military requires are tubes made out of 7075 material with specific threading and dimensions.  There are plenty of "milspec" tubes out there that are not made of 7075 but satisfy the dimensional requirements.

 

It's really not something to get all bent over as the term "milspec" is way over used and very few civilians have 100% milspec weapons....for the sole reason there's that pesky little selective fire requirement.

 

Yeah, and can assure you that if you buy a "milspec" buffer tube, regardless of what it's made of, it will fit on a "milspec" stock. A "commercial spec" tube will not. Which is why companies like Magpul make both.

 

So at least in this instance, "milspec" is only used by the industry to specify OD of the tube. And you can see the difference between the cut vs extruded threads, too.

 

 

And yeah yeah, likely hardly any AR is precisely "milspec" anymore in the sense of the military procurement usage -- indeed, many are arguably better than milspec.

 

- OS

Edited July 9, 2015 by Oh Shoot

[Garufa]

I once got all wound up about buffer tubes and what number aluminum they are made out of...ordered from Bravo Company, whose tubes are 7075 and advertised as such.  Problem solved.

[Oh Shoot]

I once got all wound up about buffer tubes and what number aluminum they are made out of...ordered from Bravo Company, whose tubes are 7075 and advertised as such.  Problem solved.

 

I don't think either alloy or either threading is gonna stand up to bashing your enemy with it like conventional stocked weapons of the past. Maybe not even once if swung like a bat.

 

- OS

Edited July 9, 2015 by Oh Shoot

[EssOne]

I don't think either alloy or either threading is gonna stand up to bashing your enemy with it like conventional stocked weapons of the past. Maybe not even once if swung like a bat.
 
- OS

Yep, it was meant for gershootenfighten, not gersmackenfighten.