While this is an outstanding design, it did not recieve the acceptence in the market place tha it should have. Outside of a few African States...sales were weak. It was made in 3 versions. The VP70 was the basic gun and included the plastic shoulderstock/holster. The VP70M is the military version. This was the version that found some acceptence in Africa. Changes to the original were cosmetic. The gun you cite is the civilan version,VP70Z, and the burst firing and shoulder stock were abandon and the pistol was sold simply as a 9mm semi auto. It was in production from 1970 to 1983 and this would indicate that H&K no longer makes parts of magazines. Perhaps you can find an aftermarket product at www.triplek.com
. Home is at: Heckler & Koch
21480 Pacific Blvd.
Sterling,Va.20166 Ph#(703)450-1900 on line at www.hk-usa.com