While researching what parts to purchase for your custom AR-15 build, you’re no doubt going to find references to ‘6061 vs 7075 aluminum.’

Aluminum has always been popular in the world of AR-15 parts. Due to its ease of fabrication, strength and corrosion resistance, most AR parts are machined from either 6061 or 7075 series aluminum.

In the world of metallurgy, aluminum is given a numerical identifier that refers to its properties. When referring to aluminum, the alloys that make up a particular series of aluminum can make a difference in its strength and performance. (Hence the debate between 6061 vs 7075 aluminum.)

So, what’s the difference between the two—let’s find out.

6061 vs 7075 Aluminum

While there are a host of opinions regarding AR parts manufactured from 6061 and 7075 aluminum, our aim is to remain objective and informative. Here are the facts regarding these two series of aluminum.

COMPOSITION 

While the alloys that make up 6061 and 7075 are similar, the actual amount of alloy agents making up each individual composition is significantly different.

The composition of 6061 aluminum includes magnesium, silicon, iron, copper, zinc, titanium, manganese, chromium and such like.

The composition of 7075 aluminum consists of the same alloys but differs in the amounts of magnesium, silicon, iron, copper, zinc, titanium, manganese, and chromium, and additional metals which make up the series.

For additional details and exact percentages, please view the following resources:

6061 – http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061t6

7075 – http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA7075T6

KEY PROPERTIES 

In the 6061 vs 7075 aluminum debate, it’s important to remember that the key properties of both types of aluminum are what make them ideal for a variety of AR parts.

  • The properties of 6061 aluminum include corrosion resistance, weldability, medium to high strength, and good workability.
  • The properties of 7075 aluminum are high strength, stress resistant, workability and improved stress-corrosion resistance.

Although 7075 aluminum does offer some additional strength over its 6061 counterpart, this does not mean 6061 is inadequate for most AR-15 applications.

STRENGTH 

Some AR-15 aficionados would declare 7075 to be superior when choosing between 6061 vs 7075 aluminum. This belief is due to the mechanical properties of 7075 aluminum.

Although the mechanical properties do differ between 6061 and 7075 aluminum, remember your AR-15 will most likely never be subjected to the extreme PSI’s listed in the following data.

6061 – MECHANICAL PROPERTIES 

  • Ultimate Tensile Strength 45000 psi
  • Tensile Yield Strength 40000 psi
  • Fatigue Strength 14000 psi
  • Shear Strength 30000 psi
  • Hardness, Rockwell 40
  • Machinability 50%

7075 – MECHANICAL PROPERTIES 

  • Ultimate Tensile Strength 83000 psi
  • Tensile Yield Strength 73000 psi
  • Fatigue Strength 23000 psi
  • Shear Strength 48000 psi
  • Hardness, Rockwell 53.5
  • Machinability 70%

DIFFERENCE

When it comes down to the final straw of the 6061 vs 7075 aluminum discussion — its personal preference. While some may prefer 7075 aluminum, others will recognize the value of 6061.

While it is important to take into account what your AR will be used for, one must also consider the fact that thousands of AR builders have used 6061 aluminum without a single issue.

Beyond the type of material your AR parts are manufactured from, how they are manufactured is the most important factor. Knowing that the manufacturer pays attention to detail and provides quality control will ultimately determine the quality of product that is produced.

If you’re still debating between the 6061 vs 7075 aluminum, remember, AR-15 Lower Receivers stands behind every product we sell by offering our exclusive 100% satisfaction guarantee.

Start your custom AR build today with a 80% Lower Jig – 2 Pack for only $199.99.

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