The HS.30 mounted a small turret with a Hispano-Suiza HS.820 20-mm autocannon and a 15×15 periscopic sight. The role of the 20-mm autocannon in German doctrine was to engage helicopters, anti-tank weapons, and light armored vehicles, thus freeing tanks to concentrate their fire against other tanks. Even with the turret, the HS.30 was fully two feet (~0.6 m) lower in height than the M113 - no small advantage on an armored battlefield. The vehicle had an onboard supply of 2,000 rounds of 20 mm ammunition. Frontal armor provided protection against 20-mm projectiles, which was stronger than comparable vehicles of other nations. The additional armor made the HS.30 four tons heavier than the M113, even though it could only carry half as many troops. For the squad members to fire their personal weapons while mounted, roof hatches had to be opened with the soldiers sticking up out of the hatches. The Germans considered this a significant disadvantage as their likely opponent, the Soviet Army, was expected to use chemical agents in any war between NATO and the Warsaw Pact.