The 20 mm rounds feed from a 10-round magazine. Image courtesy of SA-Kuva. The L-39 packed in its transit case. This was essentially how the firearm was sold in the USA beginning in the mid-1950s.

U.S. Air Force Airmen from the 1st Maintenance Squadron conventional unit, load 20 mm rounds on to a universal ammunition loading system at Joint Base Langley-Eustis, Virginia, May 1, 2018.

The 20 mm cannon is gas operated, fitted with a muzzle brake, and fed by a drum type magazine above the rear of each barrel. It holds 60 rounds of 20x110 mm ready-use ammunition, Yugoimport said ...