horizontal group shift

[karlrudin]

This one has bee puzzling more and more . I understand that with velocity change the group should either go up or down depending on velocity. But what I've been seing in my rifle /caliber is that the groups tend to close up when my load gets tighter then it starts tt open up. This is normal. BUT when it starts opening up from velocity the whole group moves left also. I've heard this happen with j bullets a very long range but I'm shooting at 100 yds. Ideas or comments?

[JSnover]

I dunno, barrel harmonics, maybe? Barrel temperature? I've had groups move on both planes just by changing lubes.

[country gent]

Due to barrel harmmonics velocites will affect group placement due to where the barrel exists the bore in its vibration pattern. Another is bedding can have an affect here also as can stresses in the barrel.I had a win target that when it started warming up would walk shots right and slightly up routinly. a click left every few shots kept it in the x 10 ring.

[jcren]

Who knows. I have a old rem 700 06 that shoots 1-1.25" left at 100yd with Remington brass compared to Winchester or lake city. Same load, same session. I just got rid of my Remington brass.