Help diagnosing low shots at 600yds

[VA_XTC_Shooter]

My thought is either you shifted the rifle butt position higher in your shoulder or your sling slipped down your arm.

I am going to test to see how much the butt position has to change to result in large POI shifts

 

[21shooter]

I would REST the rifle sandbag-rest shoot 60 rnds see what happens.
John

 

[Twdmar]

I am going to test to see how much the butt position has to change to result in large POI shifts

Even with irons this should not push you past the 7 ring.

 

[Park ranger]

Park Ranger, are you thinking that a random bur in the flash hole will cause a two foot drop in elevation? Most of the things suggested so far in this thread fall into the category of things that cause relatively small errors compared to what the OP has experienced. This problem is not some of the typical things that cause a 1 minute flyer in a half minute group. This is a huge error and it is in the same direction each time and its appearance is random. The fact that it is huge, occurs randomly and in the same direction each time are significant clues. Lets all focus on the clues.

No, sarcasm. I know the poster and just giving him the business.

 

[chkunz]

No, sarcasm. I know the poster and just giving him the business.

Now I get it completely! Way to go.

 

[Beau]

Have you thought about sight focus? Maybe lose the reticle in the black? I sincerely doubt it is ammo related.

 

[VA_XTC_Shooter]

Have you thought about sight focus? Maybe lose the reticle in the black? I sincerely doubt it is ammo related.

No, I did not change the focus during the string, nor did I lose the reticle. These would have been easy things to notice.

 

[Beau]

Sight alignment and position - that's what loses points in sling shooting.

ETA: I'd suspect the scope before ammo

 

[VA_XTC_Shooter]

Was talking to another shooter today and he was thinking the jackets failed and the core continued on and hit low on target. Anyone had Berger 75 jacket failures?

 

[rwj]

Was talking to another shooter today and he was thinking the jackets failed and the core continued on and hit low on target. Anyone had Berger 75 jacket failures?

Did the bullet leave a grease mark with land/groove lines on the target? If yes, it’s unlikely the jacket failed. If no, it could be a jacket failure...

 

[VA_XTC_Shooter]

I couldn’t see anything in the cardboard, but they did look a little different than the other shots.

 

[rwj]

The shape of the holes are definitely different. Those in the two single pictures are oblong contrasted to round like those in group picture. It appears like the projectile is tumbling. I don’t have any direct experience with jacket failures, but it makes sense that whatever part(s) continue downrange won’t be stable! I hope others that do chime into this thread...