Alder....I tamp my base wads down with around 10,000 pounds of pressure when I fire my standard trap load. Don't think looking inside the hull, or pushing hard on the handle of my MEC 600 is going to have much effect on those base wads.........
I shoot thousands of Federal paper reloads, and my method of seating base wads hasn't failed me yet........
Let the flames begin.......!!!!!!! Grant.