Standard Vepr .308 comes with a 5rd and a 10rd magazines in polymer. In the past, two companies made 30-rd metal mags, but neither produces them now. Just found out that SGM Tactical makes all-polymer 25-rounders and tried them out with my Vepr.
In this case, the stock rifle was updgraded with a hydraulic recoil buffer and TWS forend and rail top cover. The end result with 20″ barrel is a bit stout, so lightweight mags help.