6061 uppers?

[Drifter]

As for wearing out, I would like to see your worn out one, can you post that picture?

I don't see where he said worn out; only where the fit between upper and lower wore loose in his application:

What I have experienced with a 6061 receiver set when using dynamic tension with a 2-point quick adjust sling is that a really nice, tight receiver fit has been worn loose.

You said yourself in this same thread that pin rub in a lower could result in wear:

In a lower I think the Billet is more needed due to wear areas from trigger rub inside the lower...

I'm not sure why you feel that LRRPF52 must prove anything. His actual experience is in agreement with your speculation, and also with the data in links previously posted by you.