I have no information but I do have a question; what is the purpose of that screw through the left side wall up by the top of the hammer? Related to rimless extractor function?

I went back to Campbell's "Winchester Single Shot" books. Vol. 1, pp. 164-168 has photos of the rifle in this auction.  One photo shows the large head screw of the F.F. Burton extractor on the left side.  I missed that. The Burton extractor was for rimless cartridges.  Campbell tells us this rifle is from the Michael Brennan collection.

Vol. 2, pp. 127-131 tells us more about these rifles. My reading causes me to believe the rifles were originally made in rimless .30-06 caliber.  My conclusion is that the "rimmed .30-06" stems from an error (in 1913) in Winchester paperwork.

Campbell called these rifles "International Match" rifles and that's what they were.  It was (is?) a match fired at 300 meters.  The rules of the day required a competitor to use a rifle chambered for his country's military cartridge.  Not the military rifle, just the cartridge case.  That match is why we see the 1920s & 1930s era Hammerli actions with Springfield barrels.  And that match was usually won with rifles chambered for the 6.5x55 Swedish cartridge, hence it's reputation for accuracy.

The cartridge case was all that was required, not the full power military load. You can read about the loads in Hatcher's Notebook or in Sharpe's Complete Guide to Handloading.  In velocity, they were somewhere between factory .30-30 and .30-40 Krag loads and were easily something a High Wall made for smokeless powder could handle.

The rules of the day required a competitor to use a rifle chambered for his country's military cartridge.  Not the military rifle, just the cartridge case.

If Winchester adhered to the above rule, the rifles would've had to be chambered for the .30-06 rimless cartridge.

Bill Lawrence

The rifle sold for $3377 with the 10% premium.  Hopefully whoever bought it will come looking for brass if it is rimmed.

Jack

I think you can use 9.3x74R as the parent case IIRC

I'm the current owner of the rifle referenced in this thread and which was sold at auction last August.  It is most certainly chambered for the standard 30-06 rimless cartridge, and was shipped in that configuration from the factory on August 16, 1913.  I've done a considerable amount of research on these specially manufactured International Match rifles.  There is a short article in the current edition (Winter 2024) of "The Winchester Collector" that I co-authored with Bert Hartman and which we plan to expand upon in a future issue.  My recent research has uncovered a significant amount of "new" information originally published in 1913-1915 that tells a pretty complete story about these rifles, and is not included in Campbell's books or other more recent publications.   

I will have a display table at the Dakota Territory Trophy Show in Sioux Falls SD scheduled for March 23-24, 2024.  The display will feature this rifle and the story of its use in the International Union "Free Rifle" championship matchs held at Camp Perry in 1913.  If you're at the show, please stop by.

I'm not a Winchester guy, but it's topics like this one that make this site so great!
This is just fascinating history whether you're into High Walls or not! Great read!