Since you brought this up... You asked above if anyone has ever seen a receiver blow up, arguing the 7075 is overkill or that 6061 is as good as.
Well since the pressure is contained to the barrel extension, your argument might make sense until you realize that blowing up isn't why the TDP requires 7075 forged receivers. I myself have seen pin holes worn and cracks develop when stressed. This is the reason a standard was set. Though there will always be those that fire a few rounds and say parts is parts...
You can build one out of bubble gum if you wish, doesn't make it as good as or good enough.
