7075 vs. 6061 alloy for AR15 receivers

[fatelvis]

I just ventured into the 80% AR lower making hobby. I have 3 billet 6061 lowers to finish. Are they inferior to the 7075 forged lowers?

 

[AccelR8]

7075 is better because it's stronger than 6061 but In my most humble of opinions, 6061 is more than adequate.

 

[boltfluter]

Yes and no. If given the choice I would always take the 7075 version. Same material they use for the Stolle Panda actions. Just my .02

Paul

 

[mac86951]

Are you going to use your lower to pry your truck out of the mud?

Honestly, the bigger question is what are you doing after its finished? Hard coat anodize works as a bearing surface on the trigger / hammer pivot pins. If you're going to leave bare, I'd say 7075 might be a better option for bare aluminum wear resistance. The difference being seen only after what I'd estimate at 20k+ rounds and I'd guess that at that point the 6061 might have looser pivot pin holes.

For all other functions; if polymer works; 6061 is way stronger, you're fine.

-Mac

 

[AccelR8]

If you're going to leave bare, I'd say 7075 might be a better option for bare aluminum wear resistance. The difference being seen only after what I'd estimate at 20k+ rounds and I'd guess that at that point the 6061 might have looser pivot pin holes.

One could assemble with anti-rotation pins to mitigate that concern.

 

[ebb]

They make lowers out of plastic that work fine.

 

[nicholst55]

One could assemble with anti-rotation pins to mitigate that concern.

Even if the pin holes do wear, there are stainless steel bushings available that remedy that problem. You can also send your completed lower out for anodizing. The go-to guy is U.S. Anodizing.