Ok let hear it what is the difference between billiet and forged upper and lowers
From what I can find it is a minimal differance
Billiet is rated at roughly 62000-67000 psi of strength
And forged at 69000-72000 psi of strength
No AR in 5.56 will ever put that kind of force on a upper/lower
So why do people have a problem or love for one over the other
Lets see what the masters have to say
The strength mostly comes from the T6 heat treatment process, so as you pointed out there is very little (strength wise) difference between billet or forged.
One minor factor is corrosion resistance, for example the original M16's were made out of 6061 T6 forged, and the forging damaged the grain structure making it more susceptible to corrosion when in contact with the steel parts (takedown pins) whereas 7075 T6 responds very well to forging, so it's more resistant to corrosion.
But essentially the big difference is cost vs "features" kind of. If you look at an ATRS lower it's got the integral trigger guard, the flared magazine well, the unique "fences" around the components and the thicker construction will sometimes make them more rigid. Whereas a good old forged AR15 lower can be had for 150 bucks and is probably going to be lighter.
Even with 6061 T6 versus 7075 T6, the differences in strength aren't worth worrying over, so buy the lower you like the features and the fit of, and be done with it!
There are some Benelli M2's with aluminum receivers that have been retired after 250,000 shells fired through, and they could easily be put back into service with some spring replacements. The receivers are never going to wear out in any persons lifetime unless you're feeding it a constant diet of full auto fire.
