Was this virgin brass, "once fired" or range pickup?
I think Mal was right the first time and don't know why he changed his mind.
The large flashhole is characteristic of first generation Winchester NT ("unleaded") ammo. Very common in mixed fired brass, maybe an uh-oh at the factory. They have since gone to a small primer mutation.
Winchester says they are good for reloading with normal ACP data.
But you now have to be careful to sort out the small primer NTs.
5.4 grains of Unique (230 grain bullet?) is a very mild .45 ACP load and could lead to "smoking" the brass as Mal says.