Alright, a bit more information.
First, this is a Mosssberg Model 85, not an 85A-D.
According to here (which may or may not be accurate, but it is the best I can really find):
http://home.epix.net/~damguy/mossber...gun_models.htm
the Model 85 take 2 1/2 and 2 3/4 shells.
Realized that I didn't try two different brands of shells. BOth were winchester, just one was AA Heavy Target Load, one was Super X Lead Shot. So, I'll need to try a different brand.
Going downstairs to clean the bolt face and breech really good, see if that helps.