The 25-year-old Railways girl, who had the previous best of 16.39 at last year's Delhi National Open, threw the iron ball to 17.96m in her second attempt to shatter Harbans Kaur's earlier national record of 17.43m that stood since 1997.
This was Manpreet's hat-trick of gold medals at the National Open and sixth overall as she also got past the Olympics qualification mark of 17.80m.
Ace long distance runner OP Jaisha, also from Railways, who has already booked an Olympic berth in marathon, set a meet record in the 5000m in the very first event of the day.
Jaisha clocked 15:31.73 to better Preeja Sreedharan's eight-year old meet record of 15:45.96 as Railways made a clean sweep in the women's 5000m.
Sarita Singh bagged Railways the third gold of the day when she threw 58.97m in the hammer throw, while Sonam of LIC and Gunjan Singh of Railways bagged silver and bronze respectively.
The day also marked the return of Odisha sprinter Dutee Chand who represented Railways as she blazed the track in the 100m dash semi-finals.
Dutee, who had won 100m and 200m double in National Open 2013, was banned last year under IAAF's hyperandrogenism policy after tests revealed that her body produced natural levels of testosterone above permissible range.
But the Court of Arbitration for Sport, in its July verdict, suspended the "hyperandrogenism" rules, which will be scrapped if the IAAF, the world body of the sport, cannot provide new evidence.
Image: Manpreet Kaur
Photograph: SAI on Twitter