6061 T-6 vs 7075 T-6

[Thorax]

Thorax, I wouldn't want a Ti lower. It would increase weight significantly with no appreciable upside, unless you redesigned it to take advantage of the higher strength material.

How would it increase weight when mass for mass it is nearly as strong as steel but lighter than aluminum ?

Here's a thing to consider.
The handle bars on my mountain bike are 6v4al titanium, they weigh 19 grams.
That is less than 3/4 of 1 ounce.
They are stronger (by far) than the 75 gram 7075 aluminum ones out there and will not bend like the aluminum as they are designed to flex without bending (like a spring).
They also make them from chrome moly steel. The CrMo ones are in the 5-6 ounce range and have issues with strength due to being so thin to hold the weight down that far.
Carbon fibre ? too brittle and cracks or shatters with any impact.

Check into the Remington 700 Alaskan.
It has a titanium receiver and bolt.
Lighter than all get out....less than 6lbs for a 300 mag if I remember right.
Only problem, they no longer make them, and they were VERY expensive when they did (like $2k and up).

[Thorax]

This is right from Remington on the 700 Alaskan ti.

www.remington.com for a complete listing of Model 700 specialty, high performance rifles.




Model
700 Alaskan Ti
Action Bolt/Short, Long & Magnum
BBL Length 24 inches
Overall Length
41 5/8 inches (Short & Short Magnum)

42 1/2 inches (Long & Magnum)

Avg. Weight
6 lbs. (Short & Short Magnum)

6 1/4 lbs. (Long & Magnum)

Stock Material Carbon Fiber Synthetic
Stock Finish Matte
BBL Material 416 Stainless Steel
BBL Finish Satin Stainless

[ptoguy2002]

Corrosion resistance and ability to be forged-->7075

[AeroEngi]

The static strength properties (ultimate and yield) of 7075 are superior to that of 6061. 7075 also has better fatigue properties which I would assume plays a bigger role in AR-15 lowers than ultimate and yield strength do. 6061 has better weldability but that's not important for a lower. That's probably the reason why so many manufacturers use 6061 for their handguards; some pieces are welded on (e.g Daniel Defense Lite rail).

[Junkie]

How would it increase weight when mass for mass it is nearly as strong as steel but lighter than aluminum ?

Here's a thing to consider.
The handle bars on my mountain bike are 6v4al titanium, they weigh 19 grams.
That is less than 3/4 of 1 ounce.
They are stronger (by far) than the 75 gram 7075 aluminum ones out there and will not bend like the aluminum as they are designed to flex without bending (like a spring).
They also make them from chrome moly steel. The CrMo ones are in the 5-6 ounce range and have issues with strength due to being so thin to hold the weight down that far.
Carbon fibre ? too brittle and cracks or shatters with any impact.

Check into the Remington 700 Alaskan.
It has a titanium receiver and bolt.
Lighter than all get out....less than 6lbs for a 300 mag if I remember right.
Only problem, they no longer make them, and they were VERY expensive when they did (like $2k and up).

Titanium is significantly denser than aluminum. 7075 has a specific gravity of 2.81, 6-4 is 4.42. That's more than half again as dense.

Yes, you can redesign things to take advantage of the higher strength, but that takes a lot more work.

[M1NM]

Another option is Magnesium. Mag Tactical makes magnesium lowers that are significantly lighter than typical lowers. There are a few minor differences in dimensions on them, specifically the pivot pin areas are thicker and the front pivot lugs are bigger

Mag is brittle and work hardens quickly that's why they need thicker/bigger areas

[HK Dave]

Wow this is a stupid arsed argument. It doesn't make ANY difference for ANY of you. Get over it.

[Jimmybacon43]

If you really want a good lower receiver you need one forged from Valyrian steel

[BDH]

Thanks all!
Bruce