Wrong, the Brit's only have the bullet, a green tipped .224 penetrator, there is no way they would know what it was fired from, since many custom barrels use the same number of rifling's and just change the twist. But if it was a left are right hand twist might help.
Where does the green tip info come from? A link to that might be nice. If what you say is true (green tipped .224 penetrator) then is it safe to assume that only Lake City makes it?