The NEA rifles...who else is in the "Seen 'em" club?

Most ar kabooms I have seen on the Internet involved splitting of the receiver on the left side. The more catastrophic ones had the piece blown off and the top splitting. The barrel extension failed and the barrel got launched. There is a picture where a plastic lower shattered around the magwell.

You can destroy anything if you grossly exceed the design. The only way to compare the materials is to test the samples incrementally until failure. Engineering design must incorporate a SF. We cannot toss this idea because we assume any failure will be catastrophic.

When the twin towers were designed, the engineers did not think of the yield strength of steel under high heat generated by jet fuel. Hence, industry standard evolves based on lesson learnt and engineers will have to defend deviations from common practice.

The fact is that the 7 is stronger than the 6. While it probably won't make a difference in normal operation, it will provide more protection in a failure beyond normal condition. This is a hard fact. You can argue that the scenarios where this difference will have an effect is slim, but this is up to individuals to determine the risk and benefit. We should not downplay the risk and brush away the industry standard. There is never a pure engineering reason to choose a weaker material. However, business reasons such as cost and logistic are legitimate reasons too- they are not necessarily evil but are part of the reality. As long as people understand this point it is no big deal.
 
What I don't understand, is why you offered a quad rail as standard equipment rather than a superior material for your receiver. This is your first production AR why would you want to change the recipe instead of doing a perfect job first?

Most AR users are going to change the rifle to suit their needs/wants so why add an "aftermarket" accessory at the cost of user safety and final product quality? I bet said and done, your quad rail costs just as much as using 7075 in the receiver.
 
While I like the quad rail and see it as a necessity...I would definitely take 7075 over 6061 and if it cost me an extra hundred-hundred fifty bucks I'd still take it, needed or not.

I tend to agree with the line of thinking that while it probably doesn't matter...it's hard for me to personally justify taking a known step down in terms of materials strength.
 
What I don't understand, is why you offered a quad rail as standard equipment rather than a superior material for your receiver. This is your first production AR why would you want to change the recipe instead of doing a perfect job first?

Most AR users are going to change the rifle to suit their needs/wants so why add an "aftermarket" accessory at the cost of user safety and final product quality? I bet said and done, your quad rail costs just as much as using 7075 in the receiver.

Because it's OUR rifle, our design, and we'd like to limit the amount of components on it that are not ours.

We are making a rifle with 100% no US content so that we can export worldwide freely. we're not a big fan of having to put chinese plastic on our rifle because a few people may not want a quad rail.

Not to mention, it's easier, fewer parts and more versatile to do a FF front end.

If it's not your thing, then why does it concern you so much?
 
While I like the quad rail and see it as a necessity...I would definitely take 7075 over 6061 and if it cost me an extra hundred-hundred fifty bucks I'd still take it, needed or not.

I tend to agree with the line of thinking that while it probably doesn't matter...it's hard for me to personally justify taking a known step down in terms of materials strength.

I don't know where the $150 comes from. 7075-T6 alloy billet in a receiver size is not anything like $150 more than 6061.

If I had to guess why NEA is using 6061, I would imagine it has mor to do with billet availability in Canada, machinability and similar production considerations. The cost difference would be the least fo the determining factors IMHO.

IMHO, however, the ONLY part I'd care about wrt alloy used is the upper, and even then, 6061 will never be pushed to its limit in a non-full auto and non-military application. YMMV.
 
If Bushmaster can make a upper out of polymer and you don't hear them blowing up and maiming their users, I am pretty sure 6061 would provide many years of service to the end users.

I am more concern with when my XCR folding stock adapter will be ready ;)
 
I don't know where the $150 comes from. 7075-T6 alloy billet in a receiver size is not anything like $150 more than 6061.

If I had to guess why NEA is using 6061, I would imagine it has mor to do with billet availability in Canada, machinability and similar production considerations. The cost difference would be the least fo the determining factors IMHO.

IMHO, however, the ONLY part I'd care about wrt alloy used is the upper, and even then, 6061 will never be pushed to its limit in a non-full auto and non-military application. YMMV.

The Vietnam era m16s were made of the 6. They worked in the old days and will still work today. However, if things go wrong it is safe to say that the 7 gives a higher sf unless the incident is grossly over design.
 
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You also need to factor in the machine time..

Hypothetically (I have no idea what NEA's mills run them for power or usage, or what the per unit time is)

Lets say mill time costs $60 to make the math simpler...You can machine an upper in 6061 in say 20 minutes in 7075 it takes 26 becuase you need to go slower to avoid chatter.. So each upper costs $6 bucks more and instead of turning out 24 in a day per machine you only get 18... for 1000 units you have to pay a man for 13 more days... funny how it adds up...

So yo
 
Another consideration that is harder to quantify with math and statistics is overall 'quality' of machining and assembly. I'd take a flawless built AR with 6061 aluminum over a shoddily built one that is 7075 just so that it can technically be "milspec" regardless of how well the feed ramps are refined, if the staking is effective, or how clean the chamber reaming is, for example.
 
Given that the number of Kabooms is statistically insignificant, and that the vast majority of that statistically insignificant number of kabooms are a direct result of the actions of the user (reloading) - and that the reloading error must exceed proof values, and further that the net result of the change in materials will likely result in a very, very minor difference in net effect (10 stitches instead of 6) and that no 2 Kabooms result in the same net effect anyway, I'd say we have a pretty decent mole hill here. Give me a better bolt, carrier, barrel and barrel extension and I'm all good.
 
At Metal Supermarkets, yes. When you are buying bulk billets for series production, probably in 8ft lengths, that gap narrows considerably.
I'm aware. It was more to give the layman an idea of the cost difference.

That being said, I have no issues or concerns with a 6061 reciever. For 99.999% of users there will never be a problem.
 
I don't know where the $150 comes from. 7075-T6 alloy billet in a receiver size is not anything like $150 more than 6061.

If I had to guess why NEA is using 6061, I would imagine it has mor to do with billet availability in Canada, machinability and similar production considerations. The cost difference would be the least fo the determining factors IMHO.

IMHO, however, the ONLY part I'd care about wrt alloy used is the upper, and even then, 6061 will never be pushed to its limit in a non-full auto and non-military application. YMMV.

I am purely guessing, but I would think slower machining time is the big cost, not materials.

I would like to see a kaboom test. I am sure 6000 series will hold up fine. I'd rather have 7000...but as others have said, a well done 6 is better than a poorly done 7, and I am confident these are well done.
 
Neither aluminum will contain a kaboom, and the upper is not designed to. Also looking at the Ultimate tensile strengths of 6061 and 7075 in the T6 condition is kind of misleading. The fracture toughness is more relevant and they're equal. Their modulus of elasticity is roughly the same, they will deflect under load or "flex" equally.
 
For me the question is not about whether it will contain the KB...if it's blown up a barrel the receiver's not going to stop it.

The question is "what does it do while failing to contain the KB?"

That's why I would like to see a couple of uppers get destroyed. It would be nice to know that the damage a 6061 upper takes is no worse than a 7075.
 
Any reason why you're only going with a standard A2 birdcage FH. Have you considered producing your own or going with something produced in Canada?
:agree:
I was expecting the Pheniox!
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