So you use the wet tumble with steel and it takes most of the edge off?[/QUOTE]
What it does is remove a lot of the loose brass that is still hanging on after it gets cut. I've done around 750K doing it that way and it really helps keep loose brass out of the dies. Not to mention forming goes a bit easier with real clean cases.
Most guys that form the 300BO use an electric trimmer that mounts on a special die. Dillon came out with a newer beefier version of there older trimmer. I've never used the newer trimmer just the older version and it helps when it only has to trim just a few thousanths off the case....