It sounds like the major problem here is that the mouths of the brass shell casings have gotten dinged and misshapen. I can't imagine that simply tumbling them in case polishing media could somehow enlarge them by .010" as stated. Certainly, they could be larger than an unfired case if the chamber is larger diameter... they would have fireformed to fit the chamber and sprung back enough to allow extraction. But if they are dragging going back into the chambers after tumbling, I'd check to see if the mouths are just out of round. If they will still chamber as is, the next shot should iron them back out unless they have been fired so much that they need to be annealed.
