What yall don't understand is that the "Legend" was a simple engineering project dreamed up by marketing and constrained by the bean counters. One of the engineers on this project was a recent mechanical engineering graduate who didn't own a firearm and does "cosplay" for entertainment. She said they were working with the parameters they was given: Straight wall case less than 1.8" long. Must work in an AR platform. Must use the most cost effective bullets ie. 9mm. The presses used to make 9mm bullets are much faster and more efficient than the rifle bullet presses.
Handload-ability was not given the slightest consideration.
The sad thing is Winchester already had a design far more suitable than the .223 case to work with, the 9x23mm Win. In the early 1990's Winchester spent a lot of time and money developing the 9x23mm case, all they had to do was stretch it into the 9x45mm. The slightly larger diameter case would have had a bit more capacity and allowed for a little more taper in the "straight" wall cases. This would have alleviated much of the angst during the convoluted development process, which ultimately lead to the rebated-case-head design with crimped military primer. 9mm bolts are no issue for the AR platform. Standard AR magazines would require minor tweaking, but they had to do that anyway for the "Legend". 9mm bolt faces for bolt actions would have been a simple modification.
