There are 3 hazards for loading .357 loads into .38 Special brass:
1. The smaller case changes the expansion ratio and raises the pressure an unknown amount, depending on bullet and powder. You can wind up shooting .357 proof loads or more.
2. Depending on who/when made and what type, .38 Special Cases may not be up to .357 thickness/head strength.
3. When, someday, somehow, that .357+ load in a .38 Special case winds up in a .38 Special gun, guess what? That's WHEN, not IF!
And ole Elmer blew up more than one gun........
1. The smaller case changes the expansion ratio and raises the pressure an unknown amount, depending on bullet and powder. You can wind up shooting .357 proof loads or more.
2. Depending on who/when made and what type, .38 Special Cases may not be up to .357 thickness/head strength.
3. When, someday, somehow, that .357+ load in a .38 Special case winds up in a .38 Special gun, guess what? That's WHEN, not IF!
And ole Elmer blew up more than one gun........