<p>The reliability of thermal properties is vital for negative temperature coefficient (NTC)-based thermistors for gun barrel temperature sensing applications. In this paper, the effect of chromium doping on Mn_1.5Co₁Ni_0.5-xCr_xO₄ (where x = 0, 0.1, 0.2, 0.3 and 0.4)-based NTC thermistors and its structural, thermal, and electrical properties were extensively studied. The samples were prepared by conventional ball milling and sintering technique, and subsequently mixed with Bi₂O₃ and organic binder for formulating thick film thermistor pastes, printed on alumina substrates. The structural and surface chemical analysis of sintered powder were carried out by X-ray diffraction and photoelectron spectroscopy techniques, respectively, along with grain morphology analysis by field emission scanning electron microscopy. The electrical and impedance measurements of the planar fabricated thick film thermistor were carried out. The results specify that the spinel structure and electrical properties of the thermistor can be tailored based on sample composition. Room temperature and accelerated aging studies were carried out for the fabricated thermistor, and subsequently fixed on the gun barrel for its plausible use in temperature measurements.</p>