You will need the yugo lower for it to work on zastava. AK-314MS Yugo Rear-Biased Lower - RS Regulate Yugo Rear-Biased Lower Common Usage: Yugo/Serbian Type Rifles (OPAP, NPAP or M21 pattern rifles) Product Dimensions: 4.71 x 0.55 x 1.88 inches Weight: 3.0 oz Requires Upper mount rsregulate.com
AK-314MS Yugo Rear-Biased Lower - RS Regulate