I just got back from shooting 180 gr XTP's over 9.6 gr of Long Shot through my G-20 with a stock length KKM barrel. This is now the most accurate full power load that I have shot with the G-20.
Most of you can shoot better than me, but for what it is worth, shooting off hand this load put 11 of a 20 round group inside a 3 inch circle at 60 feet. The balance of rounds were within a 7 inch circle on the same center. This is definitely a load to try in a G-20.