Rangeball, can't tell you if the Parker grip will fit on your Diamond Hornet. Take the Hornet into the dealer and ask to try. Width, height, and a few more dimensions have to be taken into consideration. You can put masking tape on the riser to take up the slack if the grip is to wide. Can tell you this much, the Parker grip is supposed to be a medium height grip.

As long as kids are having fun shooting, I don't care if I shoot bad