The INSAS saw combat during the 1999 Kargil conflict with Pakistan. According to the Times of India, the rifle encountered some reliability problems in the very cold climate in which the conflict took place. Due to the cold weather, the rifle would jam occasionally and the polymer magazines would crack.[3] There were also cases where the rifle would fire on full automatic, while in three-round burst fire mode.[3] According to the manufacturers, these problems have been fixed.
After King Gyanendra seized power, relations between India and Nepal cooled, with India refusing to grant military aid. There were reports that the rifle malfunctioned in a gunbattle with Maoist insurgents, leading to many casualties.[4] This was refuted by the Indian embassy in Nepal, trials conducted before the Nepalese Army showed that the rifle was satisfactory and that the malfunctions had been due to poor handling and improper cleaning of the rifle by Nepalese soldiers.[4] These drawbacks were fixed after the Kargil Conflict in 1999.