The jawans were going to Karni Mata temple from Mahajan field firing range when the mishap occurred, SHO of Deshnok Police Station Surendra Kumar said.
The truck overturned as the driver lost control over the vehicle while trying to save a cow which came in front of it, he said.
While 12 injured were admitted to the military hospital, the other three are being treated at PBM government hospital in Bikaner, the SHO said.