If I shoot with different brands of subsonic HP .22LR I'm not surprised that I get a different POI.
I can easily understand why the vertical POI might vary, due to different BC, bullet weight, charge, etc, but why does the POI change laterally with some brands as well? I've found that the lateral difference can be as much as 1" at 55 yards. This happens even when the bullet weight and muzzle velocity are virtually the same between brands.
Is it due to barrel harmonics and/or something else? And why? I'm just intrigued.