In the past, I've heard that getting good accuracy out of "late model" Benjimans was often hit or miss. But so far (fingers crossed), I haven't yet found a pellet my 392 doesn't like. It's grouping everything at sub 1/2" @ 20 yards.
That's good you are happy with the gun. Most of the problems with accuracy from what I have seen and read was paint in the ends of the barrels. Try not to have too much fun you don't want to use it all up and become a bitter old man. ;^)