Scope issues? Muzzle brake the cause?

[yachciksc]

I have a leupold vx6-had 3-18 mounted on a defiance anti action. With a proof research 7prc barrel 1:8 twist. Currently just using factory ammo.

I shot this gun 3 times. First time I had it all sighted in. Second time to get some speed information for a leupold turret. Third time shooting this gun, more speed information and put atleast 100 rounds thru the setup prior to a hunt. Here's my issue.

The gun was on the first time when I left. Next week on a cold bore at 100 yards it didn't even hit a 16"x16" paper. Sighted it in again move "x" clicks up and put 50 rounds thru it during the whole day. Today, 100 yards again a 16"x16" paper and didn't even hit paper. Moved it up 21 clicks up on the leupold stock elevation turret.

Would unscrewing a self timing brake brake and reinstalling cause this?

During the day it will hold that sight in all day next time out it's lost.

 

[memtb]

"IF" I understand you correctly……the barrel harmonics will be affected (different) with brake on vs brake off. The bullet impact will be affected by the change in barrel harmonics….the bullet may (likely) be leaving the barrel in a different stage of the harmonic cycle! memtb

 

[milo-2]

I would make sure the scope is not slipping in the rings, and check action screw torque.
Maybe you are on to something, but failure to hit a 16x16" paper is a major shift.
Take a brake off, or exchange for a can, a 2" shift would be substantial at 100 yards.

 

[yachciksc]

Left to right it's great. Completely just vertical adjustments are needed. From visual inspection the scope isn't moving but I will have to torque things to be certain including the action screws.

 

[Darryle]

@milo-2 nailed it. Sounds exactly like a scope slipping back in the rings.

Remove the action out of the stock, remove rings and picatinny rail, clean and degrease everything, reinstall action, torque to specs, install picatinny rail with some blue Loctite torque to spec, I bed mine permanently to the action, install rings and scope and boresite.

 

[yachciksc]

I took the scope off, and that appeared tight but decided just to tear it down 100%. Next I went to the action screws, front action screw was less that hand tight, back was to specs.

You can physically see the slipping on the stock screw bases. I know this was all done to specs exactly 100 shots. Oh well get it all cleaned up, back together and dialed back in. I have the data I need regardless of point of impact for my turret.

 

[victor3ranger]

I would make sure the scope is not slipping in the rings, and check action screw torque.
Maybe you are on to something, but failure to hit a 16x16" paper is a major shift.
Take a brake off, or exchange for a can, a 2" shift would be substantial at 100 yards.

This
Sounds like something is moving, scope, action

 

[victor3ranger]

Oops just saw the last post