GRB 170306***A***, Swift-BAT refined analysis S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170306***A*** (trigger #741220) (NAME, et al., GCN Circ. xxxx). The BAT ground-calculated position is RA, Dec = 263.092, -44.759 deg which is RA(J2000) = 17h 32m 22.0s Dec(J2000) = -44d 45' 32.5" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 29%. [Description about the mask-weighted light curve] T90 (15-350 keV) is 21.0 +- 6.5 sec (estimated error including systematics). The time-averaged spectrum from T-7.0 to T+19.3 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.88 +- 0.26. The fluence in the 15-150 keV band is 8.6 +- 1.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.24 sec in the 15-150 keV band is 1.0 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/741220/BA/