No "knee-jerk reaction" here; I just happen to know a bit about this ammo.
Q3131 ammo, as sold by Winchester in the 90s, was really genuine Lake City M193, made at the Lake City Army Ammunition Plant in Independance, MO. Olin, the parent company of the ammo portion of Winchester, had the contract to operate the plant for the Army during that time. Part of that contract allowed Winchester to manufacture ammo for civilian/export sales at Lake City once the military quotas were met. That's where Q3131 comes from. The only difference was that Winchester changed the headstamp die from LC to WCC and used civilian packaging, as shown in the pics above.
The last of this ammo was manufactured in 1999, the last year of Winchester's (Olin's) contract to operate Lake City. It would appear that much of the Q3131 made in '99 used "leftover" or "bottom of the barrel" powder that had a slightly different burning rate and volume. There were at least a dozen lots of this '99 ammo that are known to have VERY high pressures and velocities, and caused problems for many people. This was a big topic of discussion for nearly a year at that time, and several of us were in contact with Olin about it. They eventually agreed to replace this ammo (on an individual basis) with the Q3131A they were selling at the time.
Q3131 was discontinued after 1999, because Federal's new parent company, Alliant TechSystems, won the Lake City contract and took over operations in 2000. Hence the appearance of "Federal XM193".
Since I *know* that Winchester/Olin doesn't have access to Lake City anymore, the chances are pretty good that they aren't making Q3131 anymore. Obviously, I *could* be mistaken, as there have been some rumors that IMI may discontinue supplying Q3131A, which has been a best-seller for Winchester, and they'd want to replace it. But I've heard nothing about it from sources I have, so I'm betting that this is really just older ammo that someone found in a warehouse someplace. Otherwise, all of the usual players would be selling it too.
-Troy