I saw that Midway had some surplus .303 British 174 gr. ball ammunition for sale for about $16.00 per box. That's a bit pricey but surefire .303 surplus has become quite rare. They advertised it as British origin, Berdan primed and no corrosive.
I ordered a few boxes and got it today. The plain brown pasteboard boxes are unmarked. The cases have no head stamps whatsoever. This is definitely "plausible deniability" ammunition. Does anyone have any idea of the specific purpose these cartridges were manufactured for? Range report to follow.....