 Two synchronized 7.62-millimeter (0.300 in) PV-1 machine guns were fitted in the fuselage with 600 rounds apiece with an OP-1 telescopic sight. It was hoped to fit another pair, but the extra weight adversely affected the aircraft's performance during tests. Two small Der-5 underwing bomb racks were fitted that could carry one 10-kilogram (22 lb) bomb apiece. Beam-type bomb racks were evaluated on the I-5 that could carry a pair of 250-kilogram (551 lb) bombs, but these had such adverse effects on its performance that they were rejected for service use. One of the tests with these racks had the aircraft diving down upon the target; the first example of dive bombing in the Soviet Union. The I-5 was also used to evaluate the accuracy of the RS-82 rocket, although they are not known to have been used by the aircraft in service.
