...not sure how helpful this will be, but after having reloaded a bunch of .38spl, I reloaded a few .357mag rounds for the first time yesterday and yeah, I did find it considerably more difficult. Seems like the instructions, eg "screw the die until it touches the case holder then back out one full turn" don't apply anymore, and you sorta have to do it by feel. I did end up having to screw the dies in much higher...
The reason I'm not sure if this is helpful is that I don't see why the dies being screwed in too deep would've caused inconsistent bullet depths. In my case, I just got a lot
more of everything, like much too big a bell from the expanding die... In any case, it can't hurt if you screw your bullet die in higher.
Again, follow Lee's instructions in the manual: "with a properly sized and expanded case, screw the die in until you feel it stop against the mouth of the shell... Back out the bullet seatin adjusting screw until you see threads, put a bullet in the case mouth and raise the ram...check the bullet depths and screw in the adjuster until the bullet seats to the bottom edge of the cannelure, then screw the entire die in 3/4 turn"
Worked like a charm with my .357!
"...cast FMJ..." Hi. It's one or the other. There's no such thing as a cast FMJ. There are plated bullets that look like FMJ's(jacketed) though. Plated bullets are loaded with cast bullet data, not jacketed data. It's important.
mini thread-hijack: Are the jacketed cast bullets you speak of also known as CMJ, or copper metal jacket? I noticed the data for those was similar to the data for lead bullets...