According to Alberto H. in Buenos Aires, who owns a couple of NP28s, they were very popular and cheap in Argentina (USD 230). According to Alberto the Argentine Bersa Thunder pistol's magazine is interchangeable with the NP28's. That gun is for sale in the US, and magazines are about USD 20 each. One of the main advantages you have by using Bersa´s ones, is that they hold 17/18 rounds (in countrys that trust their citizens). Archie in the Phillipines confirms that only a minimum adjustment in the hole where the magazine release fits is necessary. Bersa's owner is manufacturing some 170 mm long magazines for it - perfect for IPSC's Open Division.