I've posted this before (at least half-a-dozen times), but here goes again:
Lake City Army Ammunition Plant is the sole remaining small-arms ammo plant owned by the US government. Twin Cities AAP was closed in the 70s, leaving Lake City to meet all US military demands.
The government contracts out to others to run Lake City. From 1986-1999, Olin Chemical, the parent of Winchester Ammunition, held the contract to operate LC (before being purchased by Olin, Winchester Ammo was owned by Western Cartridge Company). Starting in 2000, the contract was awarded to Alliant TechSystems (ATK), and ATK selected their Federal Cartridge division to run Lake City.
Since early 2002, Lake City has been undergoing expansion to meet the exponentially-increased demands for ammo. Despite this expansion, production at Lake City has been several billion rounds short of DoD's needs, and this has resulted in the purchase of foreign ammo (used primarily for training) as well as awarding Olin a second-source contract.
Thus, Winchester (i.e., Olin) does indeed have a current contract to make small-arms ammunition for the US military. That ammo has WCC headstamps, as Olin has chosen to maintain the old Western Cartridge Company headstamp for military contract ammo for consistantcy's sake.
During the 90s, Winchester used to sell Lake City-made, WCC-marked ammo on the civilian market under the Q3131 product code. Knowing that their Lake City contract was expiring and that they would be losing access to the SCAMP machinery that produced Q3131, Olin contracted with IMI of Israel to produce M193-spec ammo for sale under the Winchester name. This ammo was sold under the Q3131A product code, and unlike the "non-A" versions, did not say "Made In the USA" on the boxes. Ammo produced by IMI for this contract was made with WCC headstamps, accomplished by simply changing out the headstamp die when necessary. Q3131A was produced from 1998-2002.
IMI discontinued/declined to renew this contract in 2002 due to the increased demand for their ammo by various world militaries. At the same time, Olin/Winchester was given a DoD contract and funds to purchase SCAMP machinery to produce Mil-Spec ammo. AFAIK, the first of this ammo was produced in late 2002 at their East Alton, IL ammo plant.
-Troy