All my rifles get IMR3031 after having learned my lesson with burned out barrels in a 6mm Rem with IMR4350 and IMR4831.
Handguns are SR7625 for target/'plinking' and SR4756 for power in 9mm,38/357,40/10mm,44sp/44m.
Hodgdon stated recently that PB,SR7625,SR4756,SR4759 will be discontinued by the end of 2014. I'm well stocked in 7625 and 4756,but will be adding more.
When I started reloading,for a S&W M10 38sp and Remington 700 6mm Rem,Remington had a 'reloading handbook' (free) and Remington and Dupont had an affiliation for cartridges/powders. Back then,Dupont made the IMRs' and SRs' and a few others. The Remington guide only listed Dupont powders,that's how I got started with the IMRs' and SRs'. I've tried Hercules H-2400 for the 357 and 44M,but always got 'dirty/unburnt powder results. When I got a chronograph,SR4756 gave me the same velocity levels(and sometimes better) as H-2400 but burnt clean.