Chuck, a 28 ga., cause, we think a barrel obstruction as we were shooting Estate reloads that were known for separating plastic from base.
My "fix" is to have Gunter fit a new old stock barrel set(the one I had for sale). The original barrels are factory S/S that are rare in the NID world. I was hoping for a 'hail Mary" to salvage the, How about some smaller gauge chamber inserts?

Walter c. Snyder