I’ve done some chrono work with
jacketed bullets over SR4756 in 38spl and 357mag; results are summed up in this chart.
Can’t agree more with Paul and Skip: starting low and watching out for pressure signs sounds like a very good idea. I’d consider starting much lower than 9.0 gr. – this charge is 2.5 gr. above current manufacturers’ recommendations... Here is what my primers looked like:
Note clear primer cratering in 10 gr. and 11 gr. charges. FWIW I am sticking with 9.5 gr. as my max charge for this load. Other powders out there will get me 1400 fps without setting any pressure records.
BTW, Paul, 6.3 gr. SR4756 under 158 gr. SJHP didn’t feel all that wimpy... in my S&W442
Mike