As many know I am not a big fan of Redding. I believe that what you are seeing is a generic coverall warning covering all dies. When I think of a compressed load I think of what we do with PPC, and 30 BR cartridges, where we have powder way up to the middle to top of the neck, and we are seating a bullet on top of that. A BRX has a bit more case capacity than a BR but the powder is down along the shoulder junction. (Never played with a BRX, but I have Dashers, and BR's.) I would not call this a compressed load, even though the bullet is going down past the should junction, there is still room for the powder to move. I think the problem is with the micrometer seaters, it places stress on them when your compressing the powder charge, and that it may cause damage to the micrometer. On the seater stem, it is just a piece of steel, I know on Wilson dies, they are soft, and can expand/mushroom out a tad bit, sometimes making changing seater stems from one die to another, a bit of a chore. I guess with a Redding die, that is not supported like a Wilson die, it could reek havoc.

O by the way, watch seating VLD bullets into the powder, as this can cause concentricity. As powder can push the boat tail one way or the other.