I've certainly seen 1 1/2-2" three shot groups go to under 3/4" with seating depth changes.
As to the tone of my post perhaps it could of been nicer. It was just a straight reply to "an accident waiting to happen" , "an action full of powder", and "never seen it change things enough to matter".
I don't have all the answers but if you really have a life time of reloading in your mirror and can say,"I've never seen it change things enough to matter" I have more answers than you.
