FMJ yaw and upset performance

[stanc]

The German ball bullet fragmented violently, but I'm not clear whether this was deliberate or accidental.

I'm inclined to think it may not have been deliberate, but rather incidental to using mild steel as jacket material. US M80 Ball has been produced in two flavors, one with a relative thick jacket of gilding metal (which yaws, but does not fragment), and the other made of thinner, mild steel (which yaws and does fragment!). I've seen belts of Vietnam-era M80 that had GM jackets, and other belts with steel jackets (it varied according to manufacturer). All of the recent M80 I've seen has had steel jackets.