I’ve loaded both the 357 Mag and the 327 Fed Mag. With the loads I use, it would take 3 or 4 charges to overflow the case. Accurate and pleasant loads, but just about impossible to see on a progressive press.

I use a RCBS Powder Check Die but was never fully comfortable relying on any mechanical device alone. When I load 9mm on my Hornady LNL progressive press, I use a powder check die. Plus, I can visually check the powder level since I can see inside the case. Very safe with 9mm, as long as I’m paying attention.

Even though I loaded many thousands of rounds of 357 using a powder check die on a progressive press, I reverted back to my Lee Turret Press for 357 using it as a single stage. The powder is dispensed by a powder measure and then put in a loading tray and visually checked using a flashlight. I also randomly sample one or two powder drops and check it on a scale.

Currently, I shoot mostly 9mm and not as many 357 as I used to. I’m very comfortable with this approach. I also don’t have to reset the Hornady LNL progressive press from 9mm to 357 and back. Once that press is working, I’m afraid to touch it. But, that's another story.

If I continued to load the 357 on a progressive press, I would use a powder check die with a very bulky powder. One that just about fills the case, so I can see. Lots of light is also important. A camera may work but I never tried one. I have a shooting friend that uses an automated 1050 with a camera to load thousands of 9mm in a single session with some success. But that is 9mm.

Good Luck!