The present invention aims at reducing the cropping losses formed during reversible multi pass hot rolling of flat ended bloom into bars by designing the preform end shapes using finite element analysis and a method to provide the designed preform end shapes to the input blooms. A three dimensional simulation of the reversible multi pass hot rolling process with flat ended input bloom predicts the formation of defective end shapes after rolling and reverse material tracking is applied to finite element simulations to obtain desired preform end shapes of the input bloom and similar simulations on the bloom with preformed end shape shows considerable reduction in cropping losses. An open die forging is used to provide the preform end shape to the input blooms obtained by reverse material tracking method and rolling of the said input blooms by ordinary rolling process shows considerable reduction in the formation of cropping loss and exhibits an effective improvement of about 1.02% in the yield of rolling process.