Otto Bock 3-barrel rifle - 16ga / 8x58r Sauer / 30-30 Win - Need help with markings

[Axel E]

The proofmarks on the left, shot barrel are visible in one of the photos. They are 16 in circle for the cartridge size, 16 for the bore diameter, imperial eagle for first proof, crown/U for view and the rare crown/superimposed S and W mark for a rifled choke bore. Paradox shot barrels were a rare option before WW1. They were made obsolete by the development of modern shotgun slugs by Brenneke, Stendebach and others. While the 1912 - 1923 proofmarks are still clear on the two top barrels, the original German ones on the bottom rifle barrel are illegible.

[mike ford]

Axel,
Thanks, that answers the question. I could see the marks but could not make them legible. It is pretty well known that I am not especially competent with a computer, I magnified the image to 250%, without improvement( the larger it got, the more blurred it got). As I said above, since you confirmed it, this is the first such gun I have seen. On reflection, I think if the barrels hadn't been re-blued, or if the flats had been made bright again, it would have been easier to read the marks.
Mike

[buckstix]

Hello Axel E and mike ford.

Thanks so much for your response - it is totally helpful to solve the mystery of this gun.

It was difficult to show the proofs of the 16ga - this is the best I coud do.

The measurements I made of the chambers and the bores at the muzzle are very accurate as posted. (+/- .0005) I suspect that the 30-30w may have originally been a 8x48r Sauer. (since the other barrel is a 8x58r "Sauer") Also, the chamber cast of the 30-30w shows a head dia of .432 which is slightly bigger than is typical for the 30-30w. It likely did not totally clean-up with a 30-30w reamer being used to re-chamber the barrel - which is original and not sleeved.

I shot the rifle barrels today. Both were loaded with the same powder charge, and same bullet weight. The two rear sight blades have the same groove depth, and are in-line with each other. They are only windage is adjustable. I'm not sure if they are intended to be used individually for each barrel - one for the 30-30w barrel, and the other for the 8x58r barrel ... I could have adjusted them independently to bring the groups to center, but left them as is for now. Both groups were high. I suspect the front sight may have been worn down over the years, or the bullet weight too light. This was just a preliminary test. Future testing may resolve this. It was very difficult to see the tiny front sight bead to get a good aim. Mechanically everything worked great and I used the set-trigger feature for all 10 shots. I'll be testing the 16ga barrel with both shot and ball next time,

crown-ws-1.jpg



crown-ws-2.jpg






targ-3bbl-1.jpg

[mike ford]

buckstix,
If you go back to my first posting, you will see where I mentioned "other less well known cartridges", the 8x48R S&S was the main one of those. You didn't show the head diameter of .432", ntil now. This supports your idea of the original chamber being 8x48R, as follows, a 30-30 reamer( head size about .422") won't quite clean up an 8.15x46 R( head size about .427") chamber, but will come very close. The chamber cast's head diameter of .432" wouldn't likely result from an 8.15x46 R chamber. To answer the question of whether it was 8x48 or 58, you will need to measure the length of the 8x58 chamber cast or see if the 30-30 chamber cast will fit entirely with in it. If if fits entirely with in the 8x58, then a 30-30 reamer would never make a "clean" chamber. This also would leave the question of why would two 8x58 chambers in the same gun have such different groove diameters. While I often find "Cartridges of the World" in error, it shows the bullet diameter of 8x48R as .316" and for the 8x58R as .322". These diameters are reasonably close to the groove diameters of the barrels under consideration. All this considered, I now believe the 30-30 chamber was first 8x48R( the 30-30 reamer would have made a proper rim recess. Presuming this is correct, your opinion that the bullets you are using are lighter than intended is correct. The 8x48R and 8x58 R had the same weight bullet ( 196 gr.) at velocities within 25 fps of each other ( 1690 vs 1665 fps). You might try heavier bullets, and instead of .308" bullets, you might try .311 or .312" bullets( group from .308 bullets is good however). There are other bullet options, but you are experienced enough to decide on those yourself. I often use 170 grain bullets to gain a little extra velocity and resize them if necessary. It may be helpful to read John Laborde's second article in a recent WAIDMANNSHEIL about "fun guns". As I recall, one of his guns is a 16ga rifle and while his is not a paradox you may glean some useful info. Good luck.
Mike