Cheers Tigershark, it makes sense that they would indicate "practice rounds" in that way for rifles too.
With the Steyr AUG, you just screw in a mighty great yellow plug into the end of the barrel (there to allow 'blowback' bolt to still function) so you can't miss the fact that its firing blanks.
I should have clicked, as being ex-AirForce this tired brain should have related the practically global standard "practice" blue colouring.
Anyways, enough of my rambling. On with the show!