The East Germans produced a very nice armorer tool chest for the AKM (MPi-KM/KMS-72), RPK (MPi-LMG) and the Makarov (Pistole – M). With the help of John Baum at GermanManuals.com, I have figured out what they all are for. Here are the ones for the Makarov.
Gauge measuring barrel protrusion. Press gauge into barrel. Front edge of slide will push front rod forward. Observe line for minimum 0.5mm protrusion