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Discussion Starter #1
Ninety degree shoulders!
https://worldwide.espacenet.com/searchResults?DB=&ST=singleline&bcId=1&locale=en_EP&page=0&query=square+shoulder+cartridge+case&return=true

I'm not sure that I like the look of the male threaded in case head in one of the patent drawings, O'Brien's female steel case head from the 1980s looked like a safer way to do it.

The comments about the headspace tolerences on nineteen teens brass are alarming
https://www.theexplora.com/the-square-shouldered-rimless-patent-cartridge-case/#respond

Just for completeness the contemporary .416 Rigby has a 45 degree shoulder
 

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I know you've got the ICL user name, but I think Mashburn had it right with the 30-degree shoulder...any more than that isn't really necessary and makes it difficult to get that "crush fit" feel when sizing cases. YMMV
 

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Remember the patent specification need not be true or factual. It is unfortunately usually written by a patent attorny that knows nothing of the area of firearms technology.

The Desiderata is comical. thinking that a square shoulder would feed better than a taper one...WOW what creative writing. Love his put down that no one can make tapered bottle-necked cartridges!!! 100 years later the case he considers defective is still here; his design isn't even a faint memory.
 

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Did anyone Else note the Split wall at the shoulder in the Cross section illustration?
That might be an Interesting Manufacturing Problem to solve economically.

Best Regards,
Chev. William
 

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Discussion Starter #5 (Edited)
I think one of the options used for achieving the square shoulder was to soft solder a brass ring onto the outside of the case.

The square shoulder idea didn't catch on and didn't survive the first world war. I'm not sure how much merit there is in steeper shoulder angles or where the sweetspot might lie for shoulder angles.

The steep and even square shoulder idea may well have been as a counter to marketing hype or ongoing claims about the supposed superiority of the then new belted cases and older rimmed cases, compared to rimless and even rimless rebated cases (the .424 Westley Richards is radically rebated, with a .404 Jeffrey body of .545" diameter and a .470" rim)

The Square shoulder idea had been applied to the .318 Westley Richards, and the square shoulder cases were used in the standard chamber.

The original .318 (.330" bullet diameter) was on a Mauser headsize case and actually has a 25 degree shoulder and less body taper than the .308 Winchester.

The shoulder position is further along the case body than on a .30-06 and the shoulder diameter is still greater than on a .308!

http://www.cip-bobp.org/homologation/uploads/tdcc/tab-i/tabical-en-page126.pdf

So the parent case was hardly likely to cause headspace problems in the first place.

Donnelly records a slightly larger case capacity for the .318 WR than for the .30-06, but they are very close, and the .318 WR appears to have been O'Neil, Keith & Hopkins inspiration for the .333 OKH, which (with a .338" bullet) was regularised as the .338-06 A Square more than 80 years later and on a longer and more tapered case.

Regarding the survival of the .318 WR

Americans didn't get much chance to buy British products because of the high croniest tarriff barriers which have always been operated by the united state, going right back to the time of Hamilton and Clay - they gave you the privilege of paying more for far poorer products.

Much of the British gun making industry was killed off by the gun controls introduced in 1920 (to head off a feared bolshevik revolution)

Following WWII, Britain had the highest tax rates in the world, in order to pay down war debts and to service a new welfare entitlement system, the top rate of income tax was 98%! I'm not sure about Westley Richards, but certainly Holland & Holland, Purdey and Rigby all ended up bankrupt in the 1940s and 50s

Some Americans did use the calibre, IIRC, Elmer Keith and Ernest Hemmingway were among them.
 
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