6061 uppers?

[500]

Are they really that much worse than 7075?

[bwaites]

Are they really that much worse than 7075?

Much softer. I think they work fine for short barreled rifles, but hanging a long barrel off them seems like a no go.

[WildBill3/75]

7075-t6 i about twice as strong as 6061-t6. If you want to save some $$$ get the forged.

[500]

I was just curious. My project has to be put on hold anyway. Been waiting for 12 months on satern but now all my $ is going to a divorce lawyer.

[KentuckyBuddha]

condolences

If I buy too much more stuff...I might be too! : /

[500]

condolences

If I buy too much more stuff...I might be too! : /

I hope not! This whole divorce thing is really hard especially when you have 4 kids 10 and under. The kids are worth much more than a grendel so oh well if it takes a couple years to get this projoect done. I wish I would have got in on that liberty buy it would have saved me dern near 400 over the satern barrel.

[KentuckyBuddha]

I was just kidding of course. Happily, while I have gotten a call from a producer working for the Maury Povich show...I have had no children pinned on me thus far. And, I have no plan to return their calls. : )

Those parts are not going to go bad, and they probably will be making parts for weapons for a while, so it is no worry but just a delay.

Levity aside, best to you and yours! Hope you all bear it as well as possible.

[Tedward]

So you guys think a Midwest Industries 6061-T6 Billet Upper is not as good or strong as a forged? The thickness is twice and now we need facts and proof of your statements.

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_ID=1180

Also what about the DPMS Flattop Lo-Pro Extruded upper7031-T6

http://www.dpmsinc.com/Flattop-Lo-Pro-Upper-Receiver_p_253.html

How about all of the extruded Free Float Hand guards that are way thinner and made of 6061?

Read this.

http://www.gunsumerreports.com/review_firearms_materials_and_processes_001.php

Not opinions, facts. Post them.

[Drifter]

...we need facts and proof of your statements.

Read this.

http://www.gunsumerreports.com/review_firearms_materials_and_processes_001.php

Not opinions, facts. Post them.

I'm not sure what you're looking for, but the link you posted supports what has already been stated in this thread. Here are a couple of quotes from your link:

...7075-T6 has nearly twice the strength of 6061-T6. Because strength also relates to hardness, 7075-T6 aluminum has a Brinell hardness of 150 and 6061-T6 aluminum has a Brinell hardness of 95. Clearly, the 7075-T6 alloy is stronger and harder than the 6061-T6 alloy and would be the better material for making upper and lower receivers.

Bottom Line:

If you are purchasing a new AR style rifle or receivers, you should make sure the receivers are made from 7075-T6 aluminum alloy material.

[500]

I would be more worried about the upper because of heat from gas and bcg friction and would the heat cause the material to expand and contract enough for stress fractures. It is just opinion but a 6061 lower wouldn't bother me at all. I think for either material it would take a pretty big hit for them to just crack as far a as dropping it is concerned. Not real sure though.

[Sputnik]

+1 Drifter, I read the article too, it seems the 6061 almost needs to be twice as thick to make up for the lack of strength. Sorry, not a fact just my opinion.

[500]

http://www.blacksheep6tactical.com/BlackSheep6Tactical-Billet-Upper-Receiver_p_12.html

This was the upper I was refering to.

[jurassic]

I know 7075 is a much more expensive, and stronger alloy. This comes from the engineers I worked with, they designed parts to compensate for the lack of strength of the softer alloy when they were told they couldn't use 7075. Heat treating helps a lot, but with forged uppers so cheap why would you want to use anything else.

[Tedward]

What I am referring to is DPMS uses those Low Profile/Slick Side Uppers on the 556 and .308. I know it has more mass and that makes them more rigid and not as brittle. I guess the difference is being brittle can break and being more pliable will absorb and hold together if there was a malfunction.

In a lower I think the Billet is more needed due to wear areas from trigger rub inside the lower, KNS anti rotation can help that, take down pins, buffer tube area and the support of the upper receiver. I guess the wakest point n my opinion is the barrel nut area can not be made thicker but the side walls can and the carrier just slides they that area.

As Bwaites said, the long heavy barrel on the barrle nut area would be the weakest part of an upper. Just wanted to hear the opinions on the difference of the brittleness and pliable relation. Has anyone had a failure of the 6061? I've seen failures of the Plastic/polymer lowers and milspec uppers that have exploded due to punched primers with backward explosions. someone here on the forum posted the picture of a milspec upper in two pieces.

[LRRPF52]

6061 Aluminum is a great alloy for certain climbing components, where the ductility of the alloy does well with loads and impact, like the weight of a climber falling and being stopped by connections.

The DPMS Claw receiver insert tool was meant for their Lo-pro Classic that came out back in the day, where they were able to source cheaper alloys, low-end components, and easier tool time to offer an AR15 for $630 retail. 6061 is easier to cut, being softer, and as mentioned, it's cheaper. They also got rid of the ejection port door, forward assist, and used a bull barrel that didn't require complex and timely profiling. Slap on a 6061 gas block, and call it good.

Anyway, the 6061 will flex more, so they are less likely to break, but will still distort under torque from the tool. If you true a thick 6061 upper, preferably with a tight extension tunnel, it can make a nice foundation for a heavy barrel or lighter gun, but impact resistance can be a different ball game, and if the anodizing isn't done deeply, I have seen a lot of flaking on them.

The benefit to 7075 T6 is that it has significantly more tensile strength than 6061, and in the AR15, receiver mate-up is better achieved with 7075 versus 6061, as the pivot pin and takedown pin lugs and bosses will wear faster with 6061. Where 6061 makes more sense is in the handguards, if using aluminum.

What I have experienced with a 6061 receiver set when using dynamic tension with a 2-point quick adjust sling is that a really nice, tight receiver fit has been worn loose. The 7075 T6 billet sets from top-end manufacturers are the ones to beat in this area.