Thanks everyone. I shot about 100 rounds today and it appears to be settling down. I ran out of Beeman hollow points so I bought some Crossman Premier hollow points and it seems to be grouping pretty well again, with an occational flyer. One interesting observation is the point of impact for different pellets of the same weight seems to be about the same. I don't recall that happening before I cleaned it. The gun also does not like Gamo Magnums or Master Points. They impact all over the place. It does seem to favor Gamo Match, Gamo Hunter, RWS Superdome, Crossman Copperheads, and Crossman Premier hollow points.
Rich