I checked last night, I have (4) AR platform arms

I didn't even know myself. I used to assemble them for retail sale back in the 1980's when about all you could get was a Mini-14 or SP1, maybe a rare AR180. Pack West Arms was my vendor.

On the 5.56 platform you can build a 9mm (with adapter block & bolt), .300, or new (HA!) .350 Legend by simply changing a few things. Namely barrel and magazine. There are many off branch caliber variations too. Each one with claims to be the latest and greatest. I see the solid carry handle uppers are actually "back" in demand! Guys are now building new "replicas" of the old Colt SP1. How things come back around! I forgot I also have an AR10, 5x less lethal than the AR15, you know!? Spread that around!

For our shooting industry and national salvation I think the AR platform is a divine (literally and metaphorically) device delivered to us all. Have fun with it and buy often.