These were used for a while in "Tin City" in Sennelager. Not sure where they came from or whether the procurement loop was "legal"!
Regarding your remark about "blue for drill ammunition", may I slightly correct you.. dark blue in the NATO marking system indicates inert ammunition for loading practice, although UK hung on to "chrome with red grooves" for drill small arms ammunition. Light blue indicates "Practice" ammunition which typically has an inert projectile, but with an "ert" propulsion system, which has caught the unwary over the years, and is capable of killing you quite severely!
Drill Inert ammunition should have "Drill INERT" marked on them in white letters.
Fully chromed small arms ammunition without the red marks should indicate an armourer's inspection round, which is made to higher tolerances than a normal drill round. Unfortunately whoever designed the 94 aiming rifle was not aware of this, and had the top round in the magazine chromed as an anti corrosion measure! (Not the only "issue" with this weapon!)