When choosing powders with similar burn speed, always look at the efficiency and resulting velocity and pressures while comparing charge weights.  A good example is looking at results of new technology Titegroup powder versus old technology powder HP-38.

9mm Luger       125 gr. SIE FMJ bullet

HP-38                          4.8 grs.     1088 fps   28,800 CUP

Titegroup                   4.4 grs.     1136 fps   30,600 CUP

38 Special         125 gr. HDY XTP bullet

HP-38                         4.9 grs.     934 fps     16,300 CUP

Titegroup                   4.6 grs.     1010 fps   15,600 CUP

45 ACP               200 gr. CAST LSWC bullet

HP-38                         5.6 grs.     914 fps     16,900 CUP

Titegroup                   5.4 grs.     957 fps     16,800 CUP

Titegroup saves money with a lower powder weight per cartridge and yet gets better velocity.  Newer technology powders deliver as good or better performance with a net savings in money spent, or allowing you to shoot more for the same money.  A Win - Win situation.