The 25-year-old Hyderabad based Gagan, who was unlucky to miss the final of the 10m Air rifle by a whisker here on August 12, just could not perform this morning and finished 35th with a total of 589, in the field of 56th shooters.
A visibly disappointed Gagan later said, '' For me Olympic was over after I failed to make it to the final of 10m Air Rifle. It is very difficult to pickup yourself from that stage.'' Debutante Sanjeev Rajput, who was one of the last qualifiers for the Games, shot slightly better than his famed colleague to end up six places higher with a score of 591.
The top eight in the field qualified for the finals.
Gagan started rather poorly shooting 98 out of 100 as there were nine shooters who had a perfect first series of 100 and 21 others had a score of 99.
The Indian's next series also was of 98 and that further eroded his chances, as 13 shot perfect 100, in the third series the Hyderabadi shooter shot 99 and midway through the match his score stood 295 out of 300.
Whatever hopes Gagan might have entertained of a come back, effectively ended when he missed four points in the fourth series in which he scored 96 and after that he shot next two series of 99 and 99 but it was the case of too little too late.
The difference between Gagan and the last qualifier was only that of five points but interestingly, seven shooters were tied at 594 and Valerian Sauveplane of France just made it to the last eight by virtue of a better count back.
Ukraine's Artur Ayvazian, who won the gold in this event last time, topped the qualifying round and had an amazing score 599 out of 600.
The 27-year-old Sanjeev Rajput had a series of 97, 100, 99, 98, 99, 98 which helped him to end up at the 26th spot.
Gagan and Sanjeev will also be taking part in the 50m Rifle 3 Positions on August 17.
''This is the event through which I got my qualification, I will try my best and let us see what happens,'' Gagan told mediapersons.
According to the stocky shooter, lack of quality ammunition during the practice sessions back home has had adverse effect on his performance. ''I am not making any excuses but it is a fact. You can not compete with the world class shooters in events like this after having not practiced with good ammunition.'' Ayvazian shot 103.7 in the final and with a total of 702.7 (599, 103.7) claimed the Gold and the silver was won by Matthew Emmons of the US with a score of 701.7 (597,104.7) and Australia's Warren Potent took the bronze with 700.5 (595, 105.5).