Hi, Big Norm,
Ammo was a problem to all the early auto pistol makers. The ammo makers were used to turning out revolver loads where consistency and exact dimensions were important, but rarely critical. If you want to have fun get a copy of U.S. Cartridges and Their Handguns by Chuck Suydam and look at the dimensions for rounds by different makers. All over the lot!
But auto pistols, as Luger collectors know better than anyone, are a lot more picky. Things have to be darn near right. I had not heard of tweaking a Borchardt spring, though I guess it could be done, and might have to be. Mostly though, the demonstrators just brought their own ammo, as Tauscher did.
A bit O.T., but one interesting sidelight of the ammo problems of those days still affects us down the decades. When the .45 ACP cartridge was first being developed, Frankford Arsenal was having problems with case length control, very critical for a round that is supported (headspaced) on the case mouth. (Browning's previous cartridges had been semi-rimmed; he probably got the idea of a rimless case from Luger.)
So the Army asked Browning to design an extractor that would be able to reach the extractor groove even if the case was shorter than standard. The "internal" extractor of the M1911, with the wide gap between breech face and extractor hook, is the result, and it has been one of the few problem areas of the pistol ever since.
Jim
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