I recently got a G20 and want to load up the same, some 180gr XTPs. Hornady #10 lists 8.2gr as max with that bullet and Longshot powder. Is that data just severely lawyered down?

I loaded up some Precision Delta 180gr bullets with 9.2gr and they were fine. Hodgdon lists 9.5gr as max with a 180gr Sierra bullet.