More than downsizing to just one caliber, I think downsizing to one load per caliber is a good idea-- at least for me. I have a favorite load for each gun/caliber I own, & have pretty much much setttled on those & got rid of everything else. I recently sold off a couple partially-full cans of gunpowder and several half- and full boxes of bullets for my 7x57 & 250-3000 rifles-- didn't get all that much money (about half of what I had in them) but it sure tidied up my reloading bench.
BTW my 38 spl load is a 158 gr lead HP over a stout charge of W231.