All the revolvers I carry are .357 Magnum.
I have been known to carry .38 +P or +P_loads in my short 2 1/2" and 2 3/4"barrel revolvers due to the shorter ejector rod, but my reloads are all .357 Magnum.
However, since I usually carry a Model 686+, a Model 66 or a Speed Six, it brings two separate speed loaders into the mix. Consequently, double checking to ensure I have a 7 shot speed loader to match the 7 shot L frame 686+, or a six shot speed loader to match a six shot K frame or Six series revolver is important.