www.geocities.com/elmgrove1765/

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"P6: AR15 receiver"

NO THIS ISN'T MINE!!!!!

holy crap

That has been up for quite a while.  I saw that and tried to design a way for it to have a bolt hold open, winter trigger guard, and allow the upper to hinge open and use standard take down pins as well as a standard buffer retaining pin, and a real safety detent system.  Basically everything interchangable with standard parts.

I never did figure out how to do it.  I always ended up with an area that was going to be too thin to be up to my standards or it was going to make the trigger guard space too small.  I wanted it to look just like a standard AR lower, only with the needed bolts and/or weld seams.  I could probably do it if I devoted myself to it but I eventually got frustrated and had to set it aside.

The closer to a standard lower that you want it look like, it becames almost exponentally harder design one that pieces together.  It could be done, I know, and possibly BATF approved as a parts kit or an 80%.  Here are your pieces, here is your fixture, weld it up and there is your AR with [i]smooth[/i] sides, and it would be NRA clean.