OK, got that, Rifle issue 194, page 27. I seem to recall the +1 and -1 were about headspace or some similar issue. The OESTERR. WAFFENFABR. GES. STEYR that Ken refers to simply means (in German), the Austrian Gun Manufacturing Company, (Ltd.) in the township of Steyr, Austria.

All firearms made in Austria around this period were, (I would have thought), proofed in Vienna with the exception of those made in Ferlach by the gun-making guild there which had it's own proof house. Steyr firearms would normally have all been proofed in Vienna. In the last 27 years or so, a proof tester from Vienna was loaned to the Steyr works to do their testing onsite as I saw his office and test-range when I was there. He was, unfortunately, at lunch.

If you have a quick look back at my past posts, you'll see that V with a crown above is a British proof mark; a View mark, meaning that the proof-master viewed it. A view mark is a standard mark used on most (all?) British firearms then, locally made or not.

The references I have are not clear what a V in a circle means but consider: "All foreign barrels and complete guns, not bearing proof marks acceptable to the British proof houses, must undergo proof, are then marked with the standard proof marks in a heavy circle...", (Wirnsberger & Steindler: The Standard Directory of Proof Marks, undated).

From the references I have here, old Gun Digests and etc., the only letter in a circle of this type and around this time used in Austria was "F" used for Foreign arms. There's nothing about a V in a circle in the 1959 Gun Digest article on Austrian Proofs, for instance.

One day, when I pull down several Steyr made arms that have no additional British marks applied, I'll see if there's a V in a circle, or if it only appears on imported firearms from Steyr with British marks. That would tend to answer the question and fill in the gaps.

That is, unless someone else can shed some light sooner...