6061 vs 7075 receiver extension

[DAP90]

What’s the major difference, if any, between a 6061 milspec diameter receiver extension and a 7075 milspec extension? I realize they’re different grades of aluminum but does it matter? Same threads I assume.

I ask because I picked up a PSA complete blemished lower and it apparently comes with a 6061 milspec diameter receiver extension. I’ve seen some complaints regarding the 6061 but fairly non-specific ones mostly relating to it not being milspec. If it doesn’t matter, great. Anyone familiar with the triggers on these?

http://palmettostatearmory.com/inde...r-magpul-acs-l-edition-black-no-magazine.html

I paid less than it’s currently listed for ($199 at the time) and feel like I got a good deal but probably should have done more research before purchasing. It was an impulse buy, I admit it.

This is my first and likely to be only AR and I’d like it to be a good one. I have some experience with an issued A2 but little with AR’s beyond that and until now, I’ve never looked into all the various options and components and what does and doesn’t matter.

I haven’t even received it yet but I finally received notice it’s shipping today.

 

[rockhopper46038]

Yield strength of 6061 is about 40,000 PSI
Yield strength of 7075 is about 73,000 PSI

Does it matter on a buffer tube? Probably not. But I like the 7075.

 

[Jackal]

It really depends on what you want. For 99.9% of AR users, 6061 is fine. Its not until you get to soldier level of abuse when 7075 is required. If it can be broken, a soldier will break it.