7.65/380 interchnable?

[Edward Tinker]

yes --- but the average person will call the 30 Luger the 7.65mm Luger

The 7.65×21mm Parabellum (designated as the 7,65 Parabellum by the C.I.P.[2] and also known as .30 Luger and 7.65mm Luger) is a pistol cartridge that was introduced in 1898 by German arms manufacturer Deutsche Waffen und Munitionsfabriken (DWM) for their new Pistol Parabellum. The primary designers were firearms designers Georg Luger and Hugo Borchardt, who developed the round from the earlier 7.65×25mm Borchardt while working at DWM.

So, you are correct, but calling it the technical name IMO throws people off - was not trying to correct you, I just don't know anyone that calls the 30 luger, the 7.65x21mm