After brief introduction to gamma ray bursts (GRB), we give a progress report on our work on a collapsar model for long period GRB. We start with a realistic presupernova model, follow collpase of an Fe core and formation of a black hole-disk system, with rotation, special relativity, MHD and composion changes. Realistic EOS is adopted. When the density along the rotation axis becomes low enough energy input is given at the base and a jet is ejected along the rotation axis. The simlation follows the jet propagation until a little after it emerges from the star. Our simulation stops when the basic physical mechanisms change after that. We explore the initial and inner boundary conditions at the base of the jet adopting the input from our earlier core collapse results as well as both hot fireball model and MHD dominated model. Since extraction of energy from a rotating black hole is among the most efficient mechanism for more energetic GRBs, our inclusion of MHD in our work will be useful.