GeorgeP:

"Laufstahl" would be barrel steel or gun barrel steel. So, the tubes would probably be German. Do you mean Australian or Austrian? If Austrian, it could be one w/ German tubes by Krupp(Krupp Laufstahl, Special Gewehr-Lauf-Stahl, Krupp-Inerso-Laufstahl).

Kind Regards,

Raimey
rse