The 24-year-old Mittal finished second on the podium after he tallied 74, one behind gold medal winner James Willett of Australia. Great Britain's Steven Scott was third on the standings with 56.
Fellow team-mate, Sangram Dahiya also featured in the top six but could manage only 24 points in the final. As per the new rules, the 50-shots double trap event has been stretched to a staggering 80 shots where elimination starts after the 30th shot in the six-man final.
While shotgun coach Marcelo Dradi called Bhardwaj's performance the best of the day, he rated Mittal as one of the world's best in this event alongside Willett.
Asian champion Mittal was in running for a gold medal but three consecutive misses in the final stages ensured a second-place finish, leaving the Australia, who missed one bird after the Indian's hatrick of misses, to run away with the top prize.
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"Last round the target was to hit 30 to enter final, so the motivation was there. Missed the last three shots because there was pressure. I felt very happy with way I performed, especially after the 24 I hit in the first round, that was bad," he said.
(REOPENS DEL 44)
India's Tejaswini Sawant finished seventh in the women's 50m rifle 3 positions event with a score of 402.4 in the final.
The mixed event got its start with the 10m air rifle event at the World Cup on Saturday with China winning the gold medal over Japan.
In an event where coordination plays a key role, Rai teamed up with Heena to finish ahead of Japan's Yukari Konishi and Tomoyuki Matsuda 5-3. Slovenia's Naphaswan Yangpaiboon and Kevin Venta were placed third.
"It was god, very interesting, opinions are still divided since it is early days. It will take to settle down. But we will have to start preparing for this in earnest as this, we assume, is going to be part of the Olympics and World Championships," Heena, a former world number one, said after the event.
World Championship and Asian Games silver medallist Jitu said, "I am trying to figure out how it works. We are having a little difficulty right now as far as coordination is concerned but once the rules gets clear it will be better for us."
So far, except for the women's trap and mixed air rifle event, Indian team has reached 10 finals in all in the ongoing tournament.