You take three 30-round magazines, cut and weld them together, stuff a couple of springs inside, and presto: an extendo 90-round Kalash super banana.
While visiting Canada, Ian with Forgotten Weapons taps in “Forgotten Weapons Field Research Assistant Clay” in a very Mr. Wizard-ish intro to take a closer look at the comically large AK mag. Then they head to the range with a full-auto RPK and things go sideways fast.
Like how sideways? Check it: