[/quote]Mine is from 1937 and has the odd chamber with no throat. [/quote]

Sounds like your rifle may be chambered in 8.15X52R.  Not sure of the details for that number. Will have to read the book further. Biggi will be here Friday,  can pick her brain in person. 

Think all target rifle calibers were "normalized" in 1908.  8.15X46R became the only cartridge allowed in matches. Not sure if the new rules effected all matches or the national matches.  I tend to think anything could be used in local matches. I seriously doubt the older rifles were parked in the closet and never used again. 

             Joe. 

Well, it's about twice as long as the 8.15X24R. Yes, that's another.  Don't have time now to translate the text. Can tell you that Frohn and Lang had something to do with it. This book is over two hundred pages. Fourteen pages on head stamps alone. 

        Joe.

thank you Joe, and a happy Thanksgiving to you and all of yours this morning. Give Biggi my regards when she arrives.

This is really getting interesting.  The x52r in the picture looks a mite fatter that the x46r. I wish I could get better quality Cerro-safe castings--new thread topic I guess.
I guess I'll have to load up a couple of the full length cases and unload them into the ground over at my sister's later this afternoon--- just to form the cases and see what they look like.   I'd do it in my back yard but I live in town and while I can get away with CB's, fireforming 8.15x ##r might strain the relationship with my neighbors a little too far. 
I don't have sights for it yet, The rear sight that came with it was incorrect, (an earlier percussion era lollipop that did not fit the mortise correctly).  Bill Loos is working on a correct diopter, and Steve Earle is working on a rib adapter scope mount.  I'll have to create a replacement pin head for the front sight.  Once I get it fitted out properly I'll post a few pictures

Bottom flat barrel stamping are mostly proof marks and a couple random letters. All are meaningless to me.  It has the crown over U with something (maybe an eagle) above that; on the barrel, breech block and the corner of the action.   It has a 172,28, and a four digit part or assembly number that differs from the one on the breech block.  There was a name engraved in a narrow band on the breech end of the barrel top flat but it appears to have been carefully peened to obliterate the name.

I just touched off two fire-forming rounds, (using the same 4759 load I use in the Staup/#3Ruger schuetzen in 8.15x46r), from the Aydt using the full length cases.  They chambered, fired, and ejected perfectly normally.  The fired cases appear to have the same shoulder slopes and tapers as unfired rws 8.15x46r brass,  though on the factory case the neck/ shoulder jointure is a bit more pronounced.   (that might well change on first firing)
A this point, to my eyes, the main difference seems to be a longer neck.

gotta do a better chamber cast,  It sure seems like the chamber cast shows an even longer neck that the full length 30-30 case yields.   What is the longest case made on a 30-30 head?

The OD of the base portion of my stop ring bullet fits equally tightly in both the fired long cases and the standard length 8.15s.  they are tight enough to shave lead if I don't flare the case mouth slightly.  the bullet bases mike at .318.

How much longer is the 32-40 than the 30-30 or the 8.15x46r.    

Now I'm wondering if someone cleaned up this rifles chamber with a 32-40 reamer.  EXCEPT, I can feel the shoulder tapering to the neck,  more of one than shows on the photo above.

I'm sure there is a simple explanation and I'm over complexicating things.

38-55 is same case as the rest and Starline made some of the original 2.125 full length ones   wonder what they'd squeeze down to.  Just remembered I have a bag or two of new 375 win brass used to make 38-55 when 38-55 was hard to find.  may run a couple through the 8.15 die and see how they measure up.