Wily William Hiccup did fine with a Navy 36 caliber and he couldn't reload it very fast no matter how many cylinders or speed strips he carried.
Only one possible solution to the man using a revolver and is afraid he will run out of shots before the bad guy does. Carry more than one gun. May I suggest something like these.
One on each hip, one in a shoulder holster, one in a boot, and one in your briefcase. Better make that brief case 50% larger and bullet proof. You will need something to hide behind while you are drawing another gun... and another...and another...and