I'm new to gun ownership. I currently have a S&W 686-6+ .357 and will take possession of a Model 60 .357 soon. I get a kick out of purchasing ammunition on line. I recently purchased a case of 38 Super thinking it would work in the 686. When the 38 Super ammo arrived, I noticed it was shorter than the typical 38 Special round. The 38 Super will fit into the cylinder of the 686 (I tried), but I haven't fired the 38 Super from the 686. These are my questions:

1. Is it safe to shoot a 38 Super round from my S&W 686-6+ .357?

2. What are the differences between a 38 Super and 38 Special round?