Scope Shifted Zero

[Mule3006Elk]

I can't for the life of me figure out what happened. Zeroed the rifle before hunting season. No adjustments were needed. I torque actions screws, base clamps, rings ect., every year. I shoot my deer no issue with said rifle. A few days later my son who has never missed a shot cleaned missed a deer from 235 yards, prone, minimal wind, very steady rest. We watched the deer for 10 minutes, walking normally, no blood, and then started feeding again. Acting 100% normal. Checked the area NO blood. I have no suspicion this deer was hit. He commented that the shot felt great. Head scratcher. No one is perfect but my son has harvested 7 big game animals and never missed a shot or wounded an animal. So I'm thinking human error or the system (gun, scope, rings). Range Finder is working perfect. I use a Kestrel for dope and have done velocity verification. Not that I needed one at 235 yards.

I shoot the rifle and POI has shifted 2" to the right. No elevation change. WTF. We carry this carry on the shoulder or on the bag. Rechecked all torque settings > no concerns.

I did some additional range work. I adjusted 8 clicks to the left. Now shooting 1" in the right. Something is wrong. Then I did a full 6" to the left and 6" up. POI within expected POA. Shifted 12" to the right and 6" down. POI within expected POA. Returned to zero and shot the exact same hole.

I dropped the rifle 18" on the right > shot, dropped on the left > shot, dropped on the turrets > shot. Same protocol from 36". No significant POI shifts identified.

This is a Vortex PST (I know) 4-16x50. 9 years old but never had any issues prior to this. I switched out the scope.

Any thoughts what happened besides it's a Vortex?

 

[Q_Sertorius]

Being off by 2” to the right at 100 yards doesn’t explain completely missing a deer at 235 yards.

How large are the groups you fired to confirm that it was off zero?

Did you check for cracked rings?

 

[displacedtexan]

Being off by 2” to the right at 100 yards doesn’t explain completely missing a deer at 235 yards.

How large are the groups you fired to confirm that it was off zero?

Did you check for cracked rings?

Treed me.

My exact first three thoughts.

 

[Mule3006Elk]

Being off by 2” to the right at 100 yards doesn’t explain completely missing a deer at 235 yards.

How large are the groups you fired to confirm that it was off zero?

Did you check for cracked rings?

Agree. Base on angle. POA frontal aspect front leg. All variable, not a perfect shot more than possible, angle, POA, it could in this case. But more interested in the scope aspect.

3/4" group 5 shots.

No indication of compromised rail (badger), precision matched rings (vortex). I pulled the scope and checked the rail torque > looks good.

This scope, prior to this, was solid. Tracked well ect. Never dropped or abused. Not getting beat on a quad gun rack. Things fail. I may not get an answer without someone looking at the internals.

Thanks for the input. Experience is gained sometimes by failures. Want to make sure there's not something I'm overlooking.

 

[ResearchinStuff]

Double check the ring clamps onto the rail, those can crack but you'd normally see it with a drop test poi change

 

[Mule3006Elk]

Double check the ring clamps onto the rail, those can crack but you'd normally see it with a drop test poi change

I should have mentioned that. Clamps and clamp screw torque look good as well.

 

[Kyguy]

How many rounds on the scope? Just curious. People don't want to believe it, but anything can fail at any time for any reason. I don't care what the brand is.

Agree with others, 2" isn't going to make a difference at 200 yds in that situation. He pulled the shot, plain and simple.

Does the rifle have a brake or can on it? Did you check to make sure they're still tight?

 

[grfox92]

I think what happened was Vortex.

Sent from my SM-S931U using Tapatalk

 

[Mule3006Elk]

How many rounds on the scope? Just curious. People don't want to believe it, but anything can fail at any time for any reason. I don't care what the brand is.

Agree with others, 2" isn't going to make a difference at 200 yds in that situation. He pulled the shot, plain and simple.

Does the rifle have a brake or can on it? Did you check to make sure they're still tight?

probably close to a 1000 rounds. No break or can.

 

[Kyguy]

I say put it back on the rifle and beat the snot out of it and see how it acts. Heck it might go another 9 years and be fine. Who knows.

 

[Wrench]

Hold the gun by the tip of the barrel. Give it a nice little wrap with a dead blow or rawhide hammer on the action and listen. You can usually hear when something is loose or broken.

 

[Mule3006Elk]

I say put it back on the rifle and beat the snot out of it and see how it acts. Heck it might go another 9 years and be fine. Who knows.

Thought about it. Problem is it failed. Random 2" shift is a lot at 100 yards. Our shots are usually 200-400 yard range. 2 MOA shift at 100 yards is a lot at 400 yards. As of right now it sits in the safe. May be going back to Vortex. Found a good deal on a NF.

 

[Q_Sertorius]

Thought about it. Problem is it failed. Random 2" shift is a lot at 100 yards. Our shots are usually 200-400 yard range. 2 MOA shift at 100 yards is a lot at 400 yards. As of right now it sits in the safe. May be going back to Vortex. Found a good deal on a NF.

I don’t want to say it, because I know that I am violently prejudiced against Vortex, but I think that’s the heart of the problem. I’ll never have faith in that brand, even though I know there are thousands of hunters out there using them every year. No data. No statistics. They are made in China and I just don’t like them.

If you don’t have faith in it, send it back.

Good luck with the NF. I’ve never used one, but I would be surprised if it didn’t serve you well.

 

[TaperPin]

I can't for the life of me figure out what happened. Zeroed the rifle before hunting season. No adjustments were needed. I torque actions screws, base clamps, rings ect., every year. I shoot my deer no issue with said rifle. A few days later my son who has never missed a shot cleaned missed a deer from 235 yards, prone, minimal wind, very steady rest. We watched the deer for 10 minutes, walking normally, no blood, and then started feeding again. Acting 100% normal. Checked the area NO blood. I have no suspicion this deer was hit. He commented that the shot felt great. Head scratcher. No one is perfect but my son has harvested 7 big game animals and never missed a shot or wounded an animal. So I'm thinking human error or the system (gun, scope, rings). Range Finder is working perfect. I use a Kestrel for dope and have done velocity verification. Not that I needed one at 235 yards.

I shoot the rifle and POI has shifted 2" to the right. No elevation change. WTF. We carry this carry on the shoulder or on the bag. Rechecked all torque settings > no concerns.

I did some additional range work. I adjusted 8 clicks to the left. Now shooting 1" in the right. Something is wrong. Then I did a full 6" to the left and 6" up. POI within expected POA. Shifted 12" to the right and 6" down. POI within expected POA. Returned to zero and shot the exact same hole.

I dropped the rifle 18" on the right > shot, dropped on the left > shot, dropped on the turrets > shot. Same protocol from 36". No significant POI shifts identified.

This is a Vortex PST (I know) 4-16x50. 9 years old but never had any issues prior to this. I switched out the scope.

Any thoughts what happened besides it's a Vortex?

With pure left or right shift I would also consider bedding might be allowing side to side movement. If the Nightforce doesn’t fix it, addressing the bedding would be my next step.

 

[Kyguy]

With pure left or right shift I would also consider bedding might be allowing side to side movement. If the Nightforce doesn’t fix it, addressing the bedding would be my next step.

I was going to mention bedding as well

 

[Mule3006Elk]

I don’t want to say it, because I know that I am violently prejudiced against Vortex, but I think that’s the heart of the problem. I’ll never have faith in that brand, even though I know there are thousands of hunters out there using them every year. No data. No statistics. They are made in China and I just don’t like them.

If you don’t have faith in it, send it back.

Good luck with the NF. I’ve never used one, but I would be surprised if it didn’t serve you well.

It's 100% fine to say it. I'm not easy offended. At the time of purchase it did fit my budget. It is what it is.
I had some other Vortex gear that I already sold. I have one active item left on a rifle and it's on the chopping block pending funds.

 

[Mule3006Elk]

With pure left or right shift I would also consider bedding might be allowing side to side movement. If the Nightforce doesn’t fix it, addressing the bedding would be my next step.

Good thought. I'll add it to my list.

 

[Tod osier]

Being off by 2” to the right at 100 yards doesn’t explain completely missing a deer at 235 yards.

These things aren't static, when a POS scope does POS scope stuff they don't get knocked off and then stay off the same amount. If the scope was off, sometimes subsequent shots will bring it back towards the original zero.

 

[Q_Sertorius]

These things aren't static, when a POS scope does POS scope stuff they don't get knocked off and then stay off the same amount. If the scope was off, sometimes subsequent shots will bring it back towards the original zero.

Fair point. But he said he checked the “new zero” with 5-shot groups.

It’s the mix of consistency and inconsistency that is so frustrating about poor quality scopes. It’s one reason I have purged my gun safe of anything and everything in which I don’t have complete confidence.

 

[Tod osier]

Fair point. But he said he checked the “new zero” with 5-shot groups.

It’s the mix of consistency and inconsistency that is so frustrating about poor quality scopes. It’s one reason I have purged my gun safe of anything and everything in which I don’t have complete confidence.

What I'm saying is that when knocked off they could be wildly off and then walk back towards the zero with that missing shot and subsequent shots and then not be horrifically off after that. The missing shot is the proverbial tapping of the turret that is too common at the range to get a POS scope to settle. When they settle they settle back around the zero (in his case 2" off), but don't hold zero between sessions.