If you look at old British literature from the period, there are all sorts of "proprietary" equipment and rifles from British Gun Makers. Just take a look at the number of types of locking mechanisms for British double rifles.
Double Gun Bolting Systems Spindles, Bites and Underlugs
Each maker creates a slightly different thing, be it cartridges, iron sights, etc, and touted as the end of history. Moderns should not get uppity: how many USB connectors are there?
The belted magnum was one solution that for a double rifle that was carried over to bolt rifles. I consider the belted cartridge a poor choice for magazine feed as I have had rim lock in a 375 H&H Magnum. I loaded 235 grain bullets, which made the cartridge shorter than the magazine box by maybe 3/8". That rifle still recoiled heavily, which caused cartridges to slide in the magazine. And during rapid fire exercises, I had the top cartridge move behind of the bottom cartridge, and then the belt of the top cartridge caught on the rim of the lower, causing a jam. I had to recognize that I had a jam, fully open the bolt, and push down on the cartridge stack, then close the bolt, to clear the jam. Those are things I would not want to do in a panic situation. I want to concentrate on the threat, not the diagnosis of a mechanical failure.
What I have found of interest, are comments from the inprint crowd that the original H&H cartridges produced less velocity, and hence, less pressure than the American standardized version. I wish I knew the original H&H pressures. But it makes sense that the original H&H cartridges were far lower pressure than what we buy over the counter today. H&H was using these things in double rifles, which are not mechanically rigid, and in WW1 era Mauser actions, where were built for a 43,000 psia 8mm cartridge
Gun Digest 1975 has an excellent article,
“A History of Proof Marks, Gun Proof in German” by Lee Kennett.
“The problem of smokeless proof was posed in a dramatic way by the Model 1888 and its commercial derivatives. In this particular case a solution was sought in the decree of 23 July 1893. This provided that such rifles be proved with a government smokeless powder known as the “4,000 atmosphere powder”, proof pressure was 4,000 metric atmospheres or 58,000 psia. The 4000 atmosphere proof was standardized for the 1893 and continued after 1911.
Rifle Magazine Issue 159 May 1995 Dear Editor pg 10
http://www.riflemagazine.com/magazine/PDF/ri159partial.pdf
Ludwig Olsen :
Mauser 98 actions produced by Mauser and DWM were proofed with two loads that produced approximately 1000 atmosphere greater pressure than normal factory rounds. That procedure was in accordance with the 1891 German proof law. Proof pressure for the Mauser 98 in 7 X57 was 4,050 atmospheres (57, 591 psi). Pressure of the normal 7 X 57 factory load with 11.2 gram bullet was given in Mauser’s 1908 patent boot as 3,050 atmosphere, or 43, 371 pounds.
While many Mausers in the 1908 Brazilian category will likely endure pressures considerably in excess of the 4,050 atmospheres proof loads, there might be some setback of the receiver locking shoulder with such high pressures
When you take pressure and convert it into loads, these are the loads that Mauser built his action to 8 mm Mauser cartridge loading. As a comparison, the loads from a 300 Win Mag. :
From
Cartridges of the World
8 mm case head diameter 0.470” Area 0.1735 square inches
300 Win Mag case head diameter 0.515” Area 0.2083 square inches
Bolt face loads
8mm (Mauser design loads) 0.1735 in ² X 43, 371 lbs/ in ² = 7, 525 lbs
300 Win Mag = 0.2083 in ² X 65,000 lbs/ in ² = 13, 539 lbs
The 300 Win Mag provides an 80% increase in bolt thrust over standard military loads.
I believe that once Winchester chambered their M70 in 375 H&H, an action made from 4140 steel, not the 1035 used in Mauser actions, that Winchester set the industry pressures at a much higher level than would be safe in military Mauser actions. But that was of no concern to Winchester, or anyone else for that matter, as the British were adhering to their Mausers and hiding their proprietary standards for the cartridges.