I have owned a PF-9 for about a year now. Tested with various ammo. To date I am getting the best groups at 15 yards with 115gr Golg dots.(2-6inches), the 124 and 147gr bullets from several makers appear to tumble, groups are still resepctable at 10-15 yards. (5-8 inches) Anyone experincing the same results that I have found ?