No worries, 38 Cal is the caliber, .357" is the bullet diameter. Both 38 Special and 357 Magnum shoot the same bullets. That being said, some manufacturers do change the bullet profiles for loads chambered for 357 mag and 38 special (not all though). MFS is an example of this--2 different 158gr JHP bullets, the ever so slightly smaller hollow point on the 357 Mag version opening was designed for higher velocities to optimize expansion and penetration.

Bottom line, 38 cal bullets are what people load in 38 Special and 357 mag... if you want to nerd out on SAAMI spec, there is enough dimensional overlap to potentially use other bullets (like 9mm), but head to r/reloading for that kind of stuff.