There was a really good writeup posted on HN a couple of weeks back, I need to locate the link. The gist was that there is a combination of factors for receiver

There was a really good writeup posted on HN a couple of weeks back, I need to locate the link. The gist was that there is a combination of factors for receiver and magazine that define the assault factors of the rifle, and anti-gun people always get pwned by being steered to minor and irrelevant differences between the military and civilian versions, and trying to define gun instead of platform. The author is a gun owner and enthusiast, but not a Wayne LaPierre.