Sighting problem

[Duuane]

Looking for thoughts and/or opinions with a sighting in issue. I won a Savage 7mm-08. I bore sighted it then shot three shots at 50 yards. I was good on the paper, so I went to 100 yards. With little adjustments, I adjusted the group to a dead center 2” high at 100, all good I thought. The next day I went out to 300 yards and shot a couple 5-6” three shot groups, not what I hoped, but I wasn’t completely satisfied with the feel of the gun rest so I didn’t get concerned. A couple days later I put a target out at 200 yards and fired 3 shots with no cross wind. The elevation and windage should have been spot on. One shot was center bull, one was 3” high and 2.5” left, the last was 3.5” high and 3.75” left. I went back and fired 2 more shots with sand bags, a dead solid cheek weld and no perceived reticle movement. Those shots were 1/2” apart but 4.5 inches left and high. I rechecked the torque on the screws for the rings and they were spot on. Any ideas why the impact would change so much. Could less than 20 shots total foul the barrel so much that the next 5-6 shots were so far off?

 

[DB29]

Did you clean it during the process?

I know there is an argument on if it is necessary but I have started a small break in on new barrels. First ten shots I clean after every shot. Next ten shots I clean after every other bullet. Then I shoot ten and see how it is grouping, if not great I clean and put another ten through. Before the end of the 40 rounds I am usually happy enough with the group to start testing rounds to see what the gun likes best.

 

[sndmn11]

Basically you are shooting 2" groups at 200 yards that are high and left?

If you want a 200yd zero just make that adjustment and confirm with a 10 shot group a few times.

 

[mt100gr.]

Which scope do you have on that rifle?

 

[Cahunter805]

You could Clean it and see what happens but I also suspect a scope issue. Also have you check the barrel channel for a generous free float. Also check the action screws and torque them.

I assume factory ammo is being used also. It might not like that certain bullet/brand.

 

[Duuane]

It's a Vortex Viper 4x16 x 44 I thoroughly cleaned the barrel after my last two shots but have not shot it since. Not being a reloader, I'm shooting factory ammo, and at $50 a box I don't want to waste ammo guessing why my shots wandered high and left for seemingly no reason.

 

[Duuane]

I'll check the free float and the action screws.

 

[ReddingArcher]

Not to sh!t on your scope, but being a vortex that would be my first guess as the culprit. I had a few vortex things and they all failed at one point or another.

 

[Duuane]

No worries, lots of products with high expectations fail the same as lesser quality things

 

[Duuane]

After a thorough cleaning and three fouling shots the elevation was back where it belonged, 2 inches high at 100 yards, and the windage was only slightly off. I made about 1 moa correction, the windage was dead center at 100 yards. I think that not cleaning it right out of the box was a mistake, and the initial sighting in although good, was altered by the rest of the shots put through it. Maybe slightly smoothing the microscopic imperfections of the milling process and leaving some bullet residue behind. I'm not saying this because I have any expertise, but because of some of the things I read on the subject. Thanks for the prior responses.