Been buying it up at Academy for the last few weeks.  Usually it all marked WCC 05 with the NATO cross.

But today, I noticed that several boxes were a mixture of the usually  headstamps and some other headstamp with the W C C spaced way out and NO nato cross  Plus those rounds had red primer sealant where the normal headstamped rounds didn't?  So I didn't buy any today.

Is it all M193 spec? Or is that a mixture of the value pack rounds of 223 not 5.56?

EPOCH (stumped)

It's all 5.56.  Most of the brass has a NATO stamp because it is used for M855 as well.  WCC with no NATO stamp is still 5.56, they just weren't going to use that brass for M855.

The sports athority in Mckinney off of 75 had about 20 + boxes as 5.00 a box.  
I only mess with XM193 or WWB, if you were looking to grab some up.

i bought a few boxes from sports authority and they were all mixed.  some had the nato stamp and some didn't.  they all shot well though.  i don't have a chrono or anything but i'm pretty sure it's all the same.