Can not believe this... I have never encountered a Steyr barrel that did not meet C.I.P. dimensions, not since 1914..... not in any caliber.
C.I.P. dimensions are 8,80 mm Zug (groove), 9,15 mm Feld (land) .... these are minimum dimensions.
To compare, a .358 Winchester fireing .358 dia. bullets, CIP dimensions are 8,89 mm Zug (groove), 9,09 mm Feld (land).
The .358 Winchester barrel is the tighter barrel and fires the .358 regulary.
The wider 9x56 Mannlicher-Schoenauer barrel fires this diameter easily.
What makes the situation quite strange is, that the original bullets were pretty slim, around .354 diameter.
I measured Kynoch, S&B, PS, and RWS to figure out this.
I feed my 9x56 with .358 dia. bullets, and it works flawlessly.
Nontheless, be responsible and work up your own load carefully.
HWL