ANDThe Astra 400 is rather unique. Although it was chambered for a full-powered 9mm round, the 9mm Largo, also known as the 9mm Bergmann-Bayard, it is designed around a simple blowback-operated action. In short, there is no locking mechanism, simply a very strong, coiled spring that encircles the barrel. Even more intriguing, the Astra was promoted heavily by Interarms as a pistol that could fire any 9mm rimless auto cartridge interchangeably. Indeed, it almost can since it is blessed with a forgiving chamber, long firing pin, and strong extractor.
This with other comments in the article seem to lead to the conclusion that, while this pistol is capable of chambering and firing 9mm para ammunition; this capability may not be built into other pistols chambered for this calibre. Which brings me to my next question - were there ANY other pistols built for this calibre? I can't seem to find any...Frankly, while the Model 400 will feed, chamber, fire and extract cartridges like the 9mm Luger and .380, it's not a sound practice unless it's an emergency. There is still plenty of Largo military ball floating around. Starline offers new 9mm Largo brass for reloading, and Hornady is currently loading the 9mm Steyr, which is very similar in dimensions to the Largo and works fine.
Cheers!
Abhijeet