Ok, I'm going to jump into this for no other reason than Jim Beam Devils Cut.

I've done quite a bit of research into plates (no real or even pretend research on my part beyond Google) and much of it started from Mick Boy's work gear thread. https://www.ar-15.co/threads/110033-...-(what-and-why)

From what I've read, M855 is the best 5.56 for defeating ceramic based armor plates and XM193 is the best for AR500 based plates. I know this is somewhat simplistic and I'd own AMI plates if they made XL but there seems to be a reason for m855.

Either way, please flame on and help me refine my understanding of 5.56 -vs- body armor.