He went on to work in armaments research and development, his innovations including an Indian 10mm light field gun and upgunning of the Sherman tanks.
His grandfather, Subedar Maya Das Jetley, held the Indian Distinguished Service Medal (IDSM), having served on the North Western frontier and in World War I; his father, Lt. Col Kundan Lal Jetley, MBE, participated with the British Expeditionary Forces in Burma and Shanghai, China during peace time, and served in World War II.
In 1948, he took part in the Jammu & Kashmir Operations of the Indo-Pakistani War, involving the re-capture of Jhangar, capture of Rajouri and the Punch linkup.
The occasion was celebrated by the Ordnance factory by firing of the first Bren Gun in the presence of Shri Rajendra Prasad, first President of India.
As Superintendent, Proof and Experiment Establishment, he conceived, planned and modernised the previous ranges to enable enhancement of indigenous production and evaluation of foreign manufacturer's claims.
In addition to the normal call of duties, he had been personally responsible for projecting new ideas which led to the improvement in the performance of various service equipments.
Due to his efforts, the production of 4.5" ammunition in the country could begin at least one year earlier than by waiting for such facility to be provided by a foreign supplier.
After war he contributed by making an assessment of the effect of Pakistani weapons which was a good guide for future improvements and defect investigations.
Later he helped in establishing the production of an anti-tank ammunition by revising acceptance criteria, after his return from the Jefferson Proving Grounds in the USA.
Besides all other achievements to his credit for making an investigation of national importance of an armament store he was awarded the commendation card of the Secretary (Defense Production) in 1977.
Jetley has written a number of technical papers on the improvement in the performance of Army equipment, including a proposal to convert Stuart tanks to APCs.
He has also published two books, one restricted for artillery officers promotion examination and one for the open market Rockets, Satellites and Guided Missiles.
His National Defence College paper on Future pattern of Weapons System (1970), led to him represent the course at the Parliamentarians' meeting on Atom Bomb considerations.