Lake City favorite "discontinued"?

I received an email from Sportsman's Guide that said:

You asked us to notify you when this item became available for purchase: 

# 136360-000-000 - 900RDS .223/5.56 55GR FMJ XM193 W/STIPPER C 

Unfortunately we have been informed that this item will not be available for purchase since it has been discontinued. 

We apologize for any inconvenience. 

If you click the link, you'll see the item in question is Federal .223 (5.56) 55-grain ammo on stripper clips manufactured at Lake City. 

But what's meant by discontinued? Not currently in production? Not being released commercially? No longer vended on clips? Lots of questions unanswered here. Enough qualifiers involved to suggest this isn't a mass outage, but something more highly defined.

It may also mean due to only sporadic availability, Sportsman's Guide is the one that's dropped the item from its catalog.

Still, this particular ammo's been a staple for AR-15 and Mini-14 shooters as long as I can remember. Anyone have additional insight here?