Another military 'roll stamp' AR-15 lower manufacture

[ObsceneJesster]

Huh?

Aerospace uses a ton of 6061 T6 and 7075 T6 Aluminum. 99% of lowers out there use the same exact material, which is aerospace quality (7075T6).

The military is no different. The majority of the skin on military helicopters, from what I remember, was 6061T6 or 7075T6 in the .030-.040 range.

Gotcha. I was under the impression that it was 7075-T7351 due to it's higher resistance to stress corrosion/cracking.

 

[IndispensableDestiny]

Do you see anywhere on Quentin Defense where it lists what kind of Aluminum they use? If it truly is "Aerospace Quality" then it should be higher grade then what JD is using which is 7075 T6. If I were into military stuff or were ex military, I would without a doubt wait a couple more weeks for the Quentin Defense lower. It looks better and it appears to be the higher grade aluminum.

M16 and M4 receivers are forged from 7075 aluminum alloy. The temper number is not relevant, that's a indicator of heat treating, not composition. The receivers are hot forged in a closed die and need to be heat treated after machining to get the proper temper.

"Billet" receivers are machined from aluminum plate, usually 7075-T6. True billets are cast logs or bars that are used for extrusions or stock for forging. Plate is rolled from ignots. You can certainly machine a slab of forged aluminum and call it a "billet" receiver, but I don't know of anybody who does. The temper comes from the parent plate.

Forged parts will stronger than than parts machined from plate. That's why the military uses them. Machined receivers are more expensive because it takes more machining time to make one from plate, rather than starting from a near net form forging. Forging has a much higher startup cost, but a lower per unit cost.

 

[ObsceneJesster]

M16 and M4 receivers are forged from 7075 aluminum alloy. The temper number is not relevant, that's a indicator of heat treating, not composition. The receivers are hot forged in a closed die and need to be heat treated after machining to get the proper temper.

"Billet" receivers are machined from aluminum plate, usually 7075-T6. True billets are cast logs or bars that are used for extrusions or stock for forging. Plate is rolled from ignots. You can certainly machine a slab of forged aluminum and call it a "billet" receiver, but I don't know of anybody who does. The temper comes from the parent plate.

Forged parts will stronger than than parts machined from plate. That's why the military uses them. Machined receivers are more expensive because it takes more machining time to make one from plate, rather than starting from a near net form forging. Forging has a much higher startup cost, but a lower per unit cost.

I know somebody who machines lowers from a forging. I took a trip to his facility and from what I could remember he would take shipments of aluminum every day. He would then cut it down and heat it up. After doing a few things, he would end up with 7075-T7351 which is supposedly extremely strong and resistive to corrosion. From what I hear and see, he is taking his aluminum to a step beyond what we normally see. Until I saw him working with aluminum, I really had no idea how much work goes into it. In the end, he said he wanted to build a high end product that nobody else has. I'd say he succeeded.

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