Difference between 7075 & 6061 buffer tubes

**kolbren** · 09-04-16, 19:53

Hey all... Is there a way to differentiate between the two types of commonly used material used to make buffer tubes? 7075 vs 6061. Is there a physical difference, size, weight, color? Just wondering if there is a way so if I were to purchase from a private individual, I would be able to tell what I'm getting. Thanks!

**ColtSeavers** · 09-04-16, 20:02

Typically, at least in time past, one could easily differentiate between the two as the 6061 was used for commercial spec receiver extensions that has larger/worse threading, a different diameter and a bizarre angled end. 7075 was typically mil spec only.

Nowadays, too many companies have decided to cheap out and use 6061 but to mil spec (dimensions) for their receiver extensions, so, ultimately, buy from a reputable, trusted manufacturer/retailer that is up front about specs/materials and stands behind their products.

Otherwise it's pretty much a crap shoot AFAIK.

**Dionysusigma** · 09-04-16, 21:45

Is the receiver extension something that has a tendency to fail? I can't recall any instances (not to say that there aren't any)...

**Alpine2k3** · 09-04-16, 21:57

Only thing that I can think of is if you ever had to mortar the rifle to get a stuck case out, your best bet is the stronger tube will survive.

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**Kenneth** · 09-04-16, 22:05

Originally Posted by Alpine2k3

Only thing that I can think of is if you ever had to mortar the rifle to get a stuck case out, your best bet is the stronger tube will survive.

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That's the only "real" failure I can see. I have seen some that were bent due to some ridiculous torture test that were done.

I also recall one being bent due to falling about 10-12 feet. Can remember if the guy was in a stand or on a roof. Either way a pretty large drop.

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**Iraqgunz** · 09-05-16, 00:07

Buy from a reputable source to start. Most MILSPEC diameter receiver extensions I have seen are made from 7075. The reason for this is quite simple. Commercial tubes are made from 6061 and are thicker to make up for the difference in tensile strength.

If you buy from SIONICS, BCM, Colt or similar you will get a legit product. One simply needs to read the SPECS.

http://sionicsweaponsystems.com/stor...3-carrier.html

http://www.bravocompanyusa.com/Milsp...milspec-re.htm

http://www.gandrtactical.com/cgi-bin...on&key=SP64072

Originally Posted by kolbren

Hey all... Is there a way to differentiate between the two types of commonly used material used to make buffer tubes? 7075 vs 6061. Is there a physical difference, size, weight, color? Just wondering if there is a way so if I were to purchase from a private individual, I would be able to tell what I'm getting. Thanks!

**TaterTot** · 09-05-16, 01:59

http://blog.onlinemetals.com/6061-vs...luminum-alloy/

"7075 is one of the strongest aluminum alloys available and while its increased cost and tougher workability may come across as obstacles, 7075 alloys are worth their price tag when it comes to applications in which its increased strength and toughness are crucial."

Is the $10 difference worth it if you have to beat some assholes face in with your stock before you have to shoot his douchbag buddy? My cheap ass will spend that $10 to avoid having a single single shot due to a bent RE. Buy from the reputable vendors named by IG and you'll have a RE that will serve you from range time to real time.

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**_Stormin_** · 09-05-16, 06:49

Saving money is saving money, but I will only do so when it is not at the expense of potential failure of the weapon. As has been said before, the potential savings is literally somewhere between $10 and $20. I know that dollars add up, and twenty here and twenty there is a hundred bucks fast. That considered, everything in the reciprocating assembly is a "must work." I'd be happier running a GI trigger and a boring free float handguard if that meant having more money to spend on a known good RE and BCG, than having any doubt as to the quality of those parts.

If you're dead set on saving keep an eye out for sales. Labor Day weekend deals haven't been as great as past years, but they're out there. Veterans Day is coming up and there are always sales then as well.

**lysander** · 09-05-16, 07:51

Originally Posted by kolbren

Hey all... Is there a way to differentiate between the two types of commonly used material used to make buffer tubes? 7075 vs 6061. Is there a physical difference, size, weight, color? Just wondering if there is a way so if I were to purchase from a private individual, I would be able to tell what I'm getting. Thanks!

Without doing destructive analysis, no, there is not a way to tell what aluminum alloy a part is made from.

I once did look at how much force it would take to break a 6061 receiver extension, it was pretty high, higher than breaking the wrist of a wooden rifle stock.

**Joe Mamma** · 09-05-16, 08:28

If there was a way to tell, I think it would be by looking inside the tube at the closed end. I think the 6061 tubes have end caps which are welded in place. I think the 7075 tubes are drilled/machined (but not all the way through). If so, the inside ends of the tubes should look different to the trained eye if you could look closely enough.

I hope someone with more information posts here or clarifies anything that I have said.

Joe Mamma