While the design of the M91 is based upon an elongated version of the AK-47 design just like its predecessor, the Zastava M76, the M91 features several modifications, bringing it closer to the Dragunov rifle. The separate stock and pistol grip used on the M76 have been replaced with a thumbhole stock made of synthetic polymer material resembling that used on the Russian rifle. The 7.62×54mmR chambering of the Zastava M91 is the same as used in the Dragunov. The 7.62×54mmR is suited for long-range use, and replaced the 8×57mm IS round in Serbian service.