I had the same problem would get big groups at 100yds ( 3-5") shooting the 395 powerbelts and 100 gr 777 pellets. Changed to 250 shockwaves and groups dropped down to 2-2.5", then changed to Kleenbore primers (was using Fed's 209A's) groups dropped to 1.75 and under at 100 yds. My goal is 2" groups at 200 yds.... then we will see.